diff --git a/Marlin/src/module/planner.cpp b/Marlin/src/module/planner.cpp
index cb8f3ea99e..0aa76d0240 100644
--- a/Marlin/src/module/planner.cpp
+++ b/Marlin/src/module/planner.cpp
@@ -1692,8 +1692,7 @@ void Planner::refresh_positioning() {
 #if ENABLED(AUTOTEMP)
 
   void Planner::autotemp_M104_M109() {
-    autotemp_enabled = parser.seen('F');
-    if (autotemp_enabled) autotemp_factor = parser.value_celsius_diff();
+    if ((autotemp_enabled = parser.seen('F'))) autotemp_factor = parser.value_float();
     if (parser.seen('S')) autotemp_min = parser.value_celsius();
     if (parser.seen('B')) autotemp_max = parser.value_celsius();
   }