diff --git a/Marlin/Marlin.h b/Marlin/Marlin.h
index 28c3250a30..697acf626a 100644
--- a/Marlin/Marlin.h
+++ b/Marlin/Marlin.h
@@ -265,7 +265,7 @@ extern int feedrate_percentage;
 
 extern bool axis_relative_modes[];
 extern bool volumetric_enabled;
-extern int extruder_multiplier[EXTRUDERS]; // sets extrude multiply factor (in percent) for each extruder individually
+extern int flow_percentage[EXTRUDERS]; // Extrusion factor for each extruder
 extern float filament_size[EXTRUDERS]; // cross-sectional area of filament (in millimeters), typically around 1.75 or 2.85, 0 disables the volumetric calculations for the extruder.
 extern float volumetric_multiplier[EXTRUDERS]; // reciprocal of cross-sectional area of filament (in square millimeters), stored this way to reduce computational burden in planner
 extern bool axis_known_position[3]; // axis[n].is_known
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 0a385622bc..870a162e51 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -320,7 +320,7 @@ static float feedrate_mm_s = MMM_TO_MMS(1500.0), saved_feedrate_mm_s;
 int feedrate_percentage = 100, saved_feedrate_percentage;
 
 bool axis_relative_modes[] = AXIS_RELATIVE_MODES;
-int extruder_multiplier[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(100);
+int flow_percentage[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(100);
 bool volumetric_enabled = false;
 float filament_size[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(DEFAULT_NOMINAL_FILAMENT_DIA);
 float volumetric_multiplier[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(1.0);
@@ -5594,7 +5594,7 @@ inline void gcode_M220() {
 inline void gcode_M221() {
   if (get_target_extruder_from_command(221)) return;
   if (code_seen('S'))
-    extruder_multiplier[target_extruder] = code_value_int();
+    flow_percentage[target_extruder] = code_value_int();
 }
 
 /**
@@ -6059,7 +6059,7 @@ inline void gcode_M400() { stepper.synchronize(); }
     //SERIAL_PROTOCOLPGM("Filament dia (measured mm):");
     //SERIAL_PROTOCOL(filament_width_meas);
     //SERIAL_PROTOCOLPGM("Extrusion ratio(%):");
-    //SERIAL_PROTOCOL(extruder_multiplier[active_extruder]);
+    //SERIAL_PROTOCOL(flow_percentage[active_extruder]);
   }
 
   /**
@@ -8431,15 +8431,18 @@ void prepare_move_to_destination() {
   static millis_t next_status_led_update_ms = 0;
 
   void handle_status_leds(void) {
-    float max_temp = 0.0;
     if (ELAPSED(millis(), next_status_led_update_ms)) {
       next_status_led_update_ms += 500; // Update every 0.5s
+      float max_temp =
+        #if HAS_TEMP_BED
+          MAX3(max_temp, thermalManager.degTargetBed(), thermalManager.degBed())
+        #else
+          0.0
+        #endif
+      ;
       HOTEND_LOOP() {
-        max_temp = max(max(max_temp, thermalManager.degHotend(e)), thermalManager.degTargetHotend(e));
+        max_temp = MAX3(max_temp, thermalManager.degHotend(e), thermalManager.degTargetHotend(e));
       }
-      #if HAS_TEMP_BED
-        max_temp = max(max(max_temp, thermalManager.degTargetBed()), thermalManager.degBed());
-      #endif
       bool new_led = (max_temp > 55.0) ? true : (max_temp < 54.0) ? false : red_led;
       if (new_led != red_led) {
         red_led = new_led;
diff --git a/Marlin/macros.h b/Marlin/macros.h
index 5eec73e343..c070569549 100644
--- a/Marlin/macros.h
+++ b/Marlin/macros.h
@@ -118,4 +118,7 @@
 
 #define CEILING(x,y) (((x) + (y) - 1) / (y))
 
+#define MAX3(a, b, c)    max(max(a, b), c)
+#define MAX4(a, b, c, d) max(max(max(a, b), c), d)
+
 #endif //__MACROS_H
diff --git a/Marlin/planner.cpp b/Marlin/planner.cpp
index 4e4d4a1893..7b0f09914b 100644
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@@ -622,11 +622,8 @@ void Planner::check_axes_activity() {
     block->steps[Z_AXIS] = labs(dz);
   #endif
 
-  block->steps[E_AXIS] = labs(de);
-  block->steps[E_AXIS] *= volumetric_multiplier[extruder];
-  block->steps[E_AXIS] *= extruder_multiplier[extruder];
-  block->steps[E_AXIS] /= 100;
-  block->step_event_count = max(block->steps[X_AXIS], max(block->steps[Y_AXIS], max(block->steps[Z_AXIS], block->steps[E_AXIS])));
+  block->steps[E_AXIS] = labs(de) * volumetric_multiplier[extruder] * flow_percentage[extruder] * 0.01 + 0.5;
+  block->step_event_count = MAX4(block->steps[X_AXIS], block->steps[Y_AXIS], block->steps[Z_AXIS], block->steps[E_AXIS]);
 
   // Bail if this is a zero-length block
   if (block->step_event_count <= dropsegments) return;
@@ -809,7 +806,7 @@ void Planner::check_axes_activity() {
     delta_mm[Y_AXIS] = dy * steps_to_mm[Y_AXIS];
     delta_mm[Z_AXIS] = dz * steps_to_mm[Z_AXIS];
   #endif
-  delta_mm[E_AXIS] = 0.01 * (de * steps_to_mm[E_AXIS]) * volumetric_multiplier[extruder] * extruder_multiplier[extruder];
+  delta_mm[E_AXIS] = 0.01 * (de * steps_to_mm[E_AXIS]) * volumetric_multiplier[extruder] * flow_percentage[extruder];
 
   if (block->steps[X_AXIS] <= dropsegments && block->steps[Y_AXIS] <= dropsegments && block->steps[Z_AXIS] <= dropsegments) {
     block->millimeters = fabs(delta_mm[E_AXIS]);
@@ -930,8 +927,8 @@ void Planner::check_axes_activity() {
     }
     ys0 = axis_segment_time[Y_AXIS][0] = ys0 + segment_time;
 
-    long max_x_segment_time = max(xs0, max(xs1, xs2)),
-         max_y_segment_time = max(ys0, max(ys1, ys2)),
+    long max_x_segment_time = MAX3(xs0, xs1, xs2),
+         max_y_segment_time = MAX3(ys0, ys1, ys2),
          min_xy_segment_time = min(max_x_segment_time, max_y_segment_time);
     if (min_xy_segment_time < MAX_FREQ_TIME) {
       float low_sf = speed_factor * min_xy_segment_time / (MAX_FREQ_TIME);
diff --git a/Marlin/ultralcd.cpp b/Marlin/ultralcd.cpp
index 2398ee7273..f6ff6eb757 100755
--- a/Marlin/ultralcd.cpp
+++ b/Marlin/ultralcd.cpp
@@ -799,15 +799,15 @@ void kill_screen(const char* lcd_msg) {
     // Flow 4:
     //
     #if EXTRUDERS == 1
-      MENU_ITEM_EDIT(int3, MSG_FLOW, &extruder_multiplier[0], 10, 999);
+      MENU_ITEM_EDIT(int3, MSG_FLOW, &flow_percentage[0], 10, 999);
     #else // EXTRUDERS > 1
-      MENU_ITEM_EDIT(int3, MSG_FLOW, &extruder_multiplier[active_extruder], 10, 999);
-      MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N1, &extruder_multiplier[0], 10, 999);
-      MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N2, &extruder_multiplier[1], 10, 999);
+      MENU_ITEM_EDIT(int3, MSG_FLOW, &flow_percentage[active_extruder], 10, 999);
+      MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N1, &flow_percentage[0], 10, 999);
+      MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N2, &flow_percentage[1], 10, 999);
       #if EXTRUDERS > 2
-        MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N3, &extruder_multiplier[2], 10, 999);
+        MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N3, &flow_percentage[2], 10, 999);
         #if EXTRUDERS > 3
-          MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N4, &extruder_multiplier[3], 10, 999);
+          MENU_ITEM_EDIT(int3, MSG_FLOW MSG_N4, &flow_percentage[3], 10, 999);
         #endif //EXTRUDERS > 3
       #endif //EXTRUDERS > 2
     #endif //EXTRUDERS > 1