diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 69b6a0ef4c..bc00113ac9 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -101,7 +101,7 @@
  * M34  - Set SD Card sorting options. (Requires SDCARD_SORT_ALPHA)
  * M42  - Change pin status via gcode: M42 P<pin> S<value>. LED pin assumed if P is omitted.
  * M43  - Display pin status, watch pins for changes, watch endstops & toggle LED, Z servo probe test, toggle pins
- * M48  - Measure Z Probe repeatability: M48 P<points> X<pos> Y<pos> V<level> E<engage> L<legs>. (Requires Z_MIN_PROBE_REPEATABILITY_TEST)
+ * M48  - Measure Z Probe repeatability: M48 P<points> X<pos> Y<pos> V<level> E<engage> L<legs> S<chizoid>. (Requires Z_MIN_PROBE_REPEATABILITY_TEST)
  * M75  - Start the print job timer.
  * M76  - Pause the print job timer.
  * M77  - Stop the print job timer.
@@ -7342,7 +7342,7 @@ inline void gcode_M42() {
    * M48: Z probe repeatability measurement function.
    *
    * Usage:
-   *   M48 <P#> <X#> <Y#> <V#> <E> <L#>
+   *   M48 <P#> <X#> <Y#> <V#> <E> <L#> <S>
    *     P = Number of sampled points (4-50, default 10)
    *     X = Sample X position
    *     Y = Sample Y position