diff --git a/app/models/p_hire.rb b/app/models/p_hire.rb
index 4992115..e5f2130 100644
--- a/app/models/p_hire.rb
+++ b/app/models/p_hire.rb
@@ -136,15 +136,15 @@ class PHire
               add_interval = (start_date_utc_mjd - @start_date.new_offset(0).mjd)
               days = 7
               if add_interval < 0
-                add_interval = -(-add_interval / days)
+                add_interval = 0
               else
                 add_interval = add_interval / days
               end
             else
               period_str = 'month'
               add_interval = ((start_date.year * 12 + start_date.month) - (@start_date.year * 12 + @start_date.month))
+              add_interval = 0 if add_interval < 0
             end
-            add_interval = 0 if add_interval < 0
             add_interval = add_interval.send(period_str)
             @start_date += add_interval
             @end_date += add_interval