diff --git a/libraries/GCS_MAVLink/GCS_Common.cpp b/libraries/GCS_MAVLink/GCS_Common.cpp
index 4f97f7662c..41fb1a6952 100644
--- a/libraries/GCS_MAVLink/GCS_Common.cpp
+++ b/libraries/GCS_MAVLink/GCS_Common.cpp
@@ -1255,10 +1255,10 @@ bool GCS_MAVLINK::set_ap_message_interval(enum ap_message id, uint16_t interval_
         }
     }
 
-    // send messages out at most once per main loop iteration:
+    // send messages out at most 80% of main loop rate
     if (interval_ms != 0 &&
-        interval_ms*1000 < AP::scheduler().get_loop_period_us()) {
-        interval_ms = AP::scheduler().get_loop_period_us()/1000;
+        interval_ms*800 < AP::scheduler().get_loop_period_us()) {
+        interval_ms = AP::scheduler().get_loop_period_us()/800.0;
     }
 
     // check if it's a specially-handled message: