diff --git a/libraries/AC_AutoTune/AC_AutoTune_Multi.cpp b/libraries/AC_AutoTune/AC_AutoTune_Multi.cpp
index ca18a5a716aef..0c7371b23eab6 100644
--- a/libraries/AC_AutoTune/AC_AutoTune_Multi.cpp
+++ b/libraries/AC_AutoTune/AC_AutoTune_Multi.cpp
@@ -517,7 +517,7 @@ void AC_AutoTune_Multi::twitching_test_rate(float angle, float rate, float rate_
         meas_angle_min = angle;
     }
 
-    // calculate early stopping time based on the time it takes to get to 75%
+    // calculate early stopping time based on the time it takes to get to 63.21%
     if (meas_rate_max < rate_target_max * 0.6321) {
         // the measurement not reached the 63.21% threshold yet
         step_time_limit_ms = (now - step_start_time_ms) * 3;
@@ -600,7 +600,7 @@ void AC_AutoTune_Multi::twitching_test_angle(float angle, float rate, float angl
         meas_rate_min = rate;
     }
 
-    // calculate early stopping time based on the time it takes to get to 75%
+    // calculate early stopping time based on the time it takes to get to 63.21%
     if (meas_angle_max < angle_target_max * 0.6321) {
         // the measurement not reached the 63.21% threshold yet
         step_time_limit_ms = (now - step_start_time_ms) * 3;