diff --git a/vendor/symposion/schedule/timetable.py b/vendor/symposion/schedule/timetable.py
index 9fcb627dfc604f20113d150d2d5c496d78ccd648..d671c74b342372d5293a7dab62f3980a0de5bb12 100644
--- a/vendor/symposion/schedule/timetable.py
+++ b/vendor/symposion/schedule/timetable.py
@@ -42,7 +42,7 @@ class TimeTable(object):
 
     @staticmethod
     def rowspan(times, start, end):
-        return times.index(end) - times.index(start)
+        return times.index(end) - times.index(start) -1
 
 
 def pairwise(iterable):