Look at the dates and times ...

The Banner date is 2012-09-11 23:59:59

9-11-2012 at 23:59:59 is the second before midnight ... meaning it expires at 9-12-2012 00:00:00 which is a second later ...


The Coupon date is 2012-09-11 00:00:00 that is midnight on 9-11-2012 ... meaning the second after 9-10-2012 11:59:59 ... so one is at exactly midnight on the date you set and the other is at midnight *after* the date you set ...


If you want the Banner to end at the end of 9-11-2012 (so it does not work on 9-12-2012) you set it to 9-11-2012 and it will end at the stroke of midnight on 9-12-2012, the start of the day for 9-12-2012 ... and it will work on 9-11-2012 but not on 9-12-2012 ...

If you want the Coupon to end at the end of 9-11-2012 (so it does not work on 9-12-2012) you set it to 9-12-2012 and it will end at the stroke of midnight on 9-12-2012, the start of the day for 9-12-2012 ... and it will work on 9-11-2012 but not work on 9-12-2012 ...