diff --git a/profile.c b/profile.c
index 8d9100bd6..ed550376b 100644
--- a/profile.c
+++ b/profile.c
@@ -1393,12 +1393,9 @@ void compare_samples(struct plot_data *e1, struct plot_data *e2, char *buf, int
 		if (data->depth > max_depth)
 			max_depth = data->depth;
 		/* Try to detect gas changes */
-		if (GET_PRESSURE(data) > last_pressure+2000)
-			last_pressure = GET_PRESSURE(data);
-		else
+		if (GET_PRESSURE(data) < last_pressure+2000)
 			bar_used += last_pressure-GET_PRESSURE(data);
 
-
 		count+=1;
 		last_sec = data->sec;
 		last_pressure = GET_PRESSURE(data);