Tweaks to Z fade behavior

Marlin/src/feature/bedlevel/bedlevel.cpp

  */
 void reset_bed_level() {
   if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("reset_bed_level");
-  set_bed_leveling_enabled(false);
-  #if ENABLED(MESH_BED_LEVELING)
-    mbl.reset();
-  #elif ENABLED(AUTO_BED_LEVELING_UBL)
+  #if ENABLED(AUTO_BED_LEVELING_UBL)
     ubl.reset();
-  #elif ENABLED(AUTO_BED_LEVELING_BILINEAR)
-    bilinear_start[X_AXIS] = bilinear_start[Y_AXIS] =
-    bilinear_grid_spacing[X_AXIS] = bilinear_grid_spacing[Y_AXIS] = 0;
-    for (uint8_t x = 0; x < GRID_MAX_POINTS_X; x++)
-      for (uint8_t y = 0; y < GRID_MAX_POINTS_Y; y++) {
-        z_values[x][y] = NAN;
-        #if ENABLED(EXTENSIBLE_UI)
-          ExtUI::onMeshUpdate(x, y, 0);
-        #endif
-      }
-  #elif ABL_PLANAR
-    planner.bed_level_matrix.set_to_identity();
+  #else
+    set_bed_leveling_enabled(false);
+    #if ENABLED(MESH_BED_LEVELING)
+      mbl.reset();
+    #elif ENABLED(AUTO_BED_LEVELING_BILINEAR)
+      bilinear_start[X_AXIS] = bilinear_start[Y_AXIS] =
+      bilinear_grid_spacing[X_AXIS] = bilinear_grid_spacing[Y_AXIS] = 0;
+      for (uint8_t x = 0; x < GRID_MAX_POINTS_X; x++)
+        for (uint8_t y = 0; y < GRID_MAX_POINTS_Y; y++) {
+          z_values[x][y] = NAN;
+          #if ENABLED(EXTENSIBLE_UI)
+            ExtUI::onMeshUpdate(x, y, 0);
+          #endif
+        }
+    #elif ABL_PLANAR
+      planner.bed_level_matrix.set_to_identity();
+    #endif
   #endif
 }
 

Marlin/src/feature/bedlevel/ubl/ubl.cpp

     const bool was_enabled = planner.leveling_active;
     set_bed_leveling_enabled(false);
     storage_slot = -1;
-    #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
-      planner.set_z_fade_height(10.0);
-    #endif
     ZERO(z_values);
     #if ENABLED(EXTENSIBLE_UI)
       for (uint8_t x = 0; x < GRID_MAX_POINTS_X; x++)

Marlin/src/module/configuration_store.cpp

           }
           else {
             ubl.reset();
-            DEBUG_ECHOLNPGM("UBL System reset()");
+            DEBUG_ECHOLNPGM("UBL reset");
           }
         }
       #endif

Marlin/src/module/planner.h

        */
       static inline float fade_scaling_factor_for_z(const float &rz) {
         static float z_fade_factor = 1;
-        if (z_fade_height) {
-          if (rz >= z_fade_height) return 0;
-          if (last_fade_z != rz) {
-            last_fade_z = rz;
-            z_fade_factor = 1 - rz * inverse_z_fade_height;
-          }
-          return z_fade_factor;
+        if (!z_fade_height) return 1;
+        if (rz >= z_fade_height) return 0;
+        if (last_fade_z != rz) {
+          last_fade_z = rz;
+          z_fade_factor = 1 - rz * inverse_z_fade_height;
         }
-        return 1;
+        return z_fade_factor;
       }
 
       FORCE_INLINE static void force_fade_recalc() { last_fade_z = -999.999f; }