diff --git a/Marlin/src/gcode/calibrate/M666.cpp b/Marlin/src/gcode/calibrate/M666.cpp
index 0f8233805..31d07185c 100644
--- a/Marlin/src/gcode/calibrate/M666.cpp
+++ b/Marlin/src/gcode/calibrate/M666.cpp
@@ -22,7 +22,7 @@
 
 #include "../../inc/MarlinConfig.h"
 
-#if ENABLED(DELTA) || ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+#if ENABLED(DELTA) || ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || Z_MULTI_ENDSTOPS
 
 #include "../gcode.h"
 
@@ -73,34 +73,23 @@
    *      Set Both: M666 Z<offset>
    */
   void GcodeSuite::M666() {
-    bool report = true;
     #if ENABLED(X_DUAL_ENDSTOPS)
-      if (parser.seen('X')) {
-        endstops.x2_endstop_adj = parser.value_linear_units();
-        report = false;
-      }
+      if (parser.seenval('X')) endstops.x2_endstop_adj = parser.value_linear_units();
     #endif
     #if ENABLED(Y_DUAL_ENDSTOPS)
-      if (parser.seen('Y')) {
-        endstops.y2_endstop_adj = parser.value_linear_units();
-        report = false;
-      }
+      if (parser.seenval('Y')) endstops.y2_endstop_adj = parser.value_linear_units();
     #endif
     #if ENABLED(Z_TRIPLE_ENDSTOPS)
-      if (parser.seen('Z')) {
-        const int ind = parser.intval('S');
+      if (parser.seenval('Z')) {
         const float z_adj = parser.value_linear_units();
+        const int ind = parser.intval('S');
         if (!ind || ind == 2) endstops.z2_endstop_adj = z_adj;
         if (!ind || ind == 3) endstops.z3_endstop_adj = z_adj;
-        report = false;
       }
     #elif Z_MULTI_ENDSTOPS
-      if (parser.seen('Z')) {
-        endstops.z2_endstop_adj = parser.value_linear_units();
-        report = false;
-      }
+      if (parser.seen('Z')) endstops.z2_endstop_adj = parser.value_linear_units();
     #endif
-    if (report) {
+    if (!parser.seen("XYZ")) {
       SERIAL_ECHOPGM("Dual Endstop Adjustment (mm): ");
       #if ENABLED(X_DUAL_ENDSTOPS)
         SERIAL_ECHOPAIR(" X2:", endstops.x2_endstop_adj);
diff --git a/Marlin/src/gcode/config/M200-M205.cpp b/Marlin/src/gcode/config/M200-M205.cpp
index ebd76cd79..c87c9b282 100644
--- a/Marlin/src/gcode/config/M200-M205.cpp
+++ b/Marlin/src/gcode/config/M200-M205.cpp
@@ -91,28 +91,19 @@ void GcodeSuite::M203() {
  *    T = Travel (non printing) moves
  */
 void GcodeSuite::M204() {
-  bool report = true;
-  if (parser.seenval('S')) { // Kept for legacy compatibility. Should NOT BE USED for new developments.
-    planner.settings.travel_acceleration = planner.settings.acceleration = parser.value_linear_units();
-    report = false;
-  }
-  if (parser.seenval('P')) {
-    planner.settings.acceleration = parser.value_linear_units();
-    report = false;
-  }
-  if (parser.seenval('R')) {
-    planner.settings.retract_acceleration = parser.value_linear_units();
-    report = false;
-  }
-  if (parser.seenval('T')) {
-    planner.settings.travel_acceleration = parser.value_linear_units();
-    report = false;
-  }
-  if (report) {
+  if (!parser.seen("PRST")) {
     SERIAL_ECHOPAIR("Acceleration: P", planner.settings.acceleration);
     SERIAL_ECHOPAIR(" R", planner.settings.retract_acceleration);
     SERIAL_ECHOLNPAIR(" T", planner.settings.travel_acceleration);
   }
+  else {
+    planner.synchronize();
+    // 'S' for legacy compatibility. Should NOT BE USED for new development
+    if (parser.seenval('S')) planner.settings.travel_acceleration = planner.settings.acceleration = parser.value_linear_units();
+    if (parser.seenval('P')) planner.settings.acceleration = parser.value_linear_units();
+    if (parser.seenval('R')) planner.settings.retract_acceleration = parser.value_linear_units();
+    if (parser.seenval('T')) planner.settings.travel_acceleration = parser.value_linear_units();
+  }
 }
 
 /**
@@ -128,6 +119,19 @@ void GcodeSuite::M204() {
  *    J = Junction Deviation (mm) (Requires JUNCTION_DEVIATION)
  */
 void GcodeSuite::M205() {
+  #if ENABLED(JUNCTION_DEVIATION)
+    #define J_PARAM  "J"
+  #else
+    #define J_PARAM 
+  #endif
+  #if HAS_CLASSIC_JERK
+    #define XYZE_PARAM "XYZE"
+  #else
+    #define XYZE_PARAM 
+  #endif
+  if (!parser.seen("BST" J_PARAM XYZE_PARAM)) return;
+
+  planner.synchronize();
   if (parser.seen('B')) planner.settings.min_segment_time_us = parser.value_ulong();
   if (parser.seen('S')) planner.settings.min_feedrate_mm_s = parser.value_linear_units();
   if (parser.seen('T')) planner.settings.min_travel_feedrate_mm_s = parser.value_linear_units();
diff --git a/Marlin/src/gcode/config/M217.cpp b/Marlin/src/gcode/config/M217.cpp
index f928e42b5..15d79da0a 100644
--- a/Marlin/src/gcode/config/M217.cpp
+++ b/Marlin/src/gcode/config/M217.cpp
@@ -66,24 +66,30 @@ void M217_report(const bool eeprom=false) {
  */
 void GcodeSuite::M217() {
 
-  bool report = true;
+  #define SPR_PARAM
+  #define XY_PARAM
 
   #if ENABLED(SINGLENOZZLE)
 
-    if (parser.seenval('S')) { report = false; const float v = parser.value_linear_units(); toolchange_settings.swap_length = constrain(v, 0, 500); }
-    if (parser.seenval('P')) { report = false; const int16_t v = parser.value_linear_units(); toolchange_settings.prime_speed = constrain(v, 10, 5400); }
-    if (parser.seenval('R')) { report = false; const int16_t v = parser.value_linear_units(); toolchange_settings.retract_speed = constrain(v, 10, 5400); }
+    #undef SPR_PARAM
+    #define SPR_PARAM "SPR"
+
+    if (parser.seenval('S')) { const float v = parser.value_linear_units(); toolchange_settings.swap_length = constrain(v, 0, 500); }
+    if (parser.seenval('P')) { const int16_t v = parser.value_linear_units(); toolchange_settings.prime_speed = constrain(v, 10, 5400); }
+    if (parser.seenval('R')) { const int16_t v = parser.value_linear_units(); toolchange_settings.retract_speed = constrain(v, 10, 5400); }
 
     #if ENABLED(SINGLENOZZLE_SWAP_PARK)
-      if (parser.seenval('X')) { report = false; toolchange_settings.change_point.x = parser.value_linear_units(); }
-      if (parser.seenval('Y')) { report = false; toolchange_settings.change_point.y = parser.value_linear_units(); }
+      #undef XY_PARAM
+      #define XY_PARAM "XY"
+      if (parser.seenval('X')) { toolchange_settings.change_point.x = parser.value_linear_units(); }
+      if (parser.seenval('Y')) { toolchange_settings.change_point.y = parser.value_linear_units(); }
     #endif
 
   #endif
 
-  if (parser.seenval('Z')) { report = false; toolchange_settings.z_raise = parser.value_linear_units(); }
+  if (parser.seenval('Z')) { toolchange_settings.z_raise = parser.value_linear_units(); }
 
-  if (report) M217_report();
+  if (!parser.seen(SPR_PARAM XY_PARAM "Z")) M217_report();
 
 }
 
diff --git a/Marlin/src/gcode/config/M218.cpp b/Marlin/src/gcode/config/M218.cpp
index 784ffc222..4f7a353ae 100644
--- a/Marlin/src/gcode/config/M218.cpp
+++ b/Marlin/src/gcode/config/M218.cpp
@@ -42,21 +42,11 @@
 void GcodeSuite::M218() {
   if (get_target_extruder_from_command() || target_extruder == 0) return;
 
-  bool report = true;
-  if (parser.seenval('X')) {
-    hotend_offset[X_AXIS][target_extruder] = parser.value_linear_units();
-    report = false;
-  }
-  if (parser.seenval('Y')) {
-    hotend_offset[Y_AXIS][target_extruder] = parser.value_linear_units();
-    report = false;
-  }
-  if (parser.seenval('Z')) {
-    hotend_offset[Z_AXIS][target_extruder] = parser.value_linear_units();
-    report = false;
-  }
+  if (parser.seenval('X')) hotend_offset[X_AXIS][target_extruder] = parser.value_linear_units();
+  if (parser.seenval('Y')) hotend_offset[Y_AXIS][target_extruder] = parser.value_linear_units();
+  if (parser.seenval('Z')) hotend_offset[Z_AXIS][target_extruder] = parser.value_linear_units();
 
-  if (report) {
+  if (!parser.seen("XYZ")) {
     SERIAL_ECHO_START();
     SERIAL_ECHOPGM(MSG_HOTEND_OFFSET);
     HOTEND_LOOP() {
diff --git a/Marlin/src/gcode/gcode.h b/Marlin/src/gcode/gcode.h
index 7ce952173..c697e33c0 100644
--- a/Marlin/src/gcode/gcode.h
+++ b/Marlin/src/gcode/gcode.h
@@ -749,7 +749,7 @@ private:
     static void M665();
   #endif
 
-  #if ENABLED(DELTA) || ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || ENABLED(Z_DUAL_ENDSTOPS)
+  #if ENABLED(DELTA) || ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || Z_MULTI_ENDSTOPS
     static void M666();
   #endif
 
diff --git a/Marlin/src/gcode/parser.h b/Marlin/src/gcode/parser.h
index 9c9f47997..38a5455b6 100644
--- a/Marlin/src/gcode/parser.h
+++ b/Marlin/src/gcode/parser.h
@@ -19,6 +19,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+#pragma once
 
 /**
  * parser.h - Parser for a GCode line, providing a parameter interface.
@@ -26,9 +27,6 @@
  *           so settings for these codes are located in this class.
  */
 
-#ifndef _PARSER_H_
-#define _PARSER_H_
-
 #include "../inc/MarlinConfig.h"
 
 //#define DEBUG_GCODE_PARSER
@@ -115,7 +113,7 @@ public:
     }
 
     // Set the flag and pointer for a parameter
-    static void set(const char c, char * const ptr) {
+    static inline void set(const char c, char * const ptr) {
       const uint8_t ind = LETTER_BIT(c);
       if (ind >= COUNT(param)) return;           // Only A-Z
       SBI32(codebits, ind);                      // parameter exists
@@ -132,7 +130,7 @@ public:
 
     // Code seen bit was set. If not found, value_ptr is unchanged.
     // This allows "if (seen('A')||seen('B'))" to use the last-found value.
-    static bool seen(const char c) {
+    static inline bool seen(const char c) {
       const uint8_t ind = LETTER_BIT(c);
       if (ind >= COUNT(param)) return false; // Only A-Z
       const bool b = TEST32(codebits, ind);
@@ -143,7 +141,34 @@ public:
       return b;
     }
 
-    static bool seen_any() { return !!codebits; }
+    FORCE_INLINE static constexpr uint32_t letter_bits(const char * const str) {
+      return  (str[0] ? _BV32(LETTER_BIT(str[0])) |
+              (str[1] ? _BV32(LETTER_BIT(str[1])) |
+              (str[2] ? _BV32(LETTER_BIT(str[2])) |
+              (str[3] ? _BV32(LETTER_BIT(str[3])) |
+              (str[4] ? _BV32(LETTER_BIT(str[4])) |
+              (str[5] ? _BV32(LETTER_BIT(str[5])) |
+              (str[6] ? _BV32(LETTER_BIT(str[6])) |
+              (str[7] ? _BV32(LETTER_BIT(str[7])) |
+              (str[8] ? _BV32(LETTER_BIT(str[8])) |
+              (str[9] ? _BV32(LETTER_BIT(str[9]))
+            : 0) : 0) : 0) : 0) : 0) : 0) : 0) : 0) : 0) : 0);
+    }
+
+    // At least one of a list of code letters was seen
+    #ifdef CPU_32_BIT
+      FORCE_INLINE static bool seen(const char * const str) { return !!(codebits & letter_bits(str)); }
+    #else
+      // At least one of a list of code letters was seen
+      FORCE_INLINE static bool seen(const char * const str) {
+        const uint32_t letrbits = letter_bits(str);
+        const uint8_t * const cb = (uint8_t*)&codebits;
+        const uint8_t * const lb = (uint8_t*)&letrbits;
+        return (cb[0] & lb[0]) || (cb[1] & lb[1]) || (cb[2] & lb[2]) || (cb[3] & lb[3]);
+      }
+    #endif
+
+    static inline bool seen_any() { return !!codebits; }
 
     #define SEEN_TEST(L) TEST32(codebits, LETTER_BIT(L))
 
@@ -151,21 +176,28 @@ public:
 
     // Code is found in the string. If not found, value_ptr is unchanged.
     // This allows "if (seen('A')||seen('B'))" to use the last-found value.
-    static bool seen(const char c) {
+    static inline bool seen(const char c) {
       char *p = strchr(command_args, c);
       const bool b = !!p;
       if (b) value_ptr = valid_float(&p[1]) ? &p[1] : (char*)NULL;
       return b;
     }
 
-    static bool seen_any() { return *command_args == '\0'; }
+    static inline bool seen_any() { return *command_args == '\0'; }
 
     #define SEEN_TEST(L) !!strchr(command_args, L)
 
+    // At least one of a list of code letters was seen
+    static inline bool seen(const char * const str) {
+      for (uint8_t i = 0; const char c = str[i]; i++)
+        if (SEEN_TEST(c)) return true;
+      return false;
+    }
+
   #endif // !FASTER_GCODE_PARSER
 
   // Seen any axis parameter
-  static bool seen_axis() {
+  static inline bool seen_axis() {
     return SEEN_TEST('X') || SEEN_TEST('Y') || SEEN_TEST('Z') || SEEN_TEST('E');
   }
 
@@ -348,5 +380,3 @@ public:
 };
 
 extern GCodeParser parser;
-
-#endif // _PARSER_H_