Index: industry_cmd.cpp
===================================================================
--- industry_cmd.cpp	(revision 27682)
+++ industry_cmd.cpp	(working copy)
@@ -2570,8 +2570,8 @@
 			}
 		} else {
 			if (only_decrease || Chance16(1, 3)) {
-				/* If more than 60% transported, 66% chance of increase, else 33% chance of increase */
-				if (!only_decrease && (i->last_month_pct_transported[0] > PERCENT_TRANSPORTED_60) != Chance16(1, 3)) {
+				/* If more than 60% transported, 66% chance of increase with bonus for very high ratings, else 33% chance of increase */
+				if (!only_decrease && (i->last_month_pct_transported[0] > PERCENT_TRANSPORTED_60) != Chance16(1, ((i->last_month_pct_transported[0] > PERCENT_TRANSPORTED_80) ? 6 : 3))) {
 					mul = 1; // Increase production
 				} else {
 					div = 1; // Decrease production