Correct EEPROM read/write disparities. (#12169)

Marlin/src/module/configuration_store.cpp

  */
 
 // Change EEPROM version if the structure changes
-#define EEPROM_VERSION "V61"
+#define EEPROM_VERSION "V62"
 #define EEPROM_OFFSET 100
 
 // Check the integrity of data offsets.
   #elif ENABLED(X_DUAL_ENDSTOPS) || ENABLED(Y_DUAL_ENDSTOPS) || Z_MULTI_ENDSTOPS
     float x2_endstop_adj,                               // M666 X
           y2_endstop_adj,                               // M666 Y
-          z2_endstop_adj;                               // M666 Z
-    #if ENABLED(Z_TRIPLE_ENDSTOPS)
-      float z3_endstop_adj;                             // M666 Z
-    #endif
+          z2_endstop_adj,                               // M666 Z (S2)
+          z3_endstop_adj;                               // M666 Z (S3)
   #endif
 
   //
     // SINGLENOZZLE
     //
 
-    #if ENABLED(SINGLENOZZLE)
+    #if EXTRUDERS > 1
       _FIELD_TEST(toolchange_settings);
       EEPROM_WRITE(toolchange_settings);
     #endif
       //
       // SINGLENOZZLE toolchange values
       //
-      #if ENABLED(SINGLENOZZLE)
+      #if EXTRUDERS > 1
         _FIELD_TEST(toolchange_settings);
         EEPROM_READ(toolchange_settings);
       #endif
   #endif
 
   #if EXTRUDERS > 1
-    toolchange_settings.z_raise = TOOLCHANGE_ZRAISE;
-  #endif
-  
-  #if ENABLED(SINGLENOZZLE)
-    toolchange_settings.swap_length = SINGLENOZZLE_SWAP_LENGTH;
-    toolchange_settings.prime_speed = SINGLENOZZLE_SWAP_PRIME_SPEED;
-    toolchange_settings.retract_speed = SINGLENOZZLE_SWAP_RETRACT_SPEED;
-    #if ENABLED(SINGLENOZZLE_SWAP_PARK)
-      toolchange_settings.change_point = SINGLENOZZLE_TOOLCHANGE_XY;
+    #if ENABLED(SINGLENOZZLE)
+      toolchange_settings.swap_length = SINGLENOZZLE_SWAP_LENGTH;
+      toolchange_settings.prime_speed = SINGLENOZZLE_SWAP_PRIME_SPEED;
+      toolchange_settings.retract_speed = SINGLENOZZLE_SWAP_RETRACT_SPEED;
+      #if ENABLED(SINGLENOZZLE_SWAP_PARK)
+        toolchange_settings.change_point = SINGLENOZZLE_TOOLCHANGE_XY;
+      #endif
     #endif
+    toolchange_settings.z_raise = TOOLCHANGE_ZRAISE;
   #endif
 
   //

Marlin/src/module/tool_change.h

 #if EXTRUDERS > 1
 
   typedef struct {
-    float swap_length;
-    int16_t prime_speed, retract_speed;
-    #if ENABLED(SINGLENOZZLE_SWAP_PARK)
-      struct { float x, y; } change_point;
+    #if ENABLED(SINGLENOZZLE)
+      float swap_length;
+      int16_t prime_speed, retract_speed;
+      #if ENABLED(SINGLENOZZLE_SWAP_PARK)
+        struct { float x, y; } change_point;
+      #endif
     #endif
-    float z_raise = TOOLCHANGE_ZRAISE;
+    float z_raise;
   } toolchange_settings_t;
 
   extern toolchange_settings_t toolchange_settings;