If you're getting to Wembley then you expect PL oppo, but that still only makes 9.
Just to be clear about that run for United:
City (PL) - Jan 12 - FA Cup
Liverpool (PL) - Jan 12 - FA Cup
Newcastle (PL) - Sep 12 - Lge Cup
Chelsea (PL) - Oct 12 - Lge Cup
W Ham (PL) - Jan 13 - FA Cup
Fulham (PL) - Jan 13 - FA Cup
Reading (PL) - Feb 13 - FA Cup
Chelsea (PL) - Mar 13 - FA Cup
Chelsea (PL) - Apr 13 - FA Cup - REPLAY
Liverpool (PL) - Sep 13 - Lge Cup
Norwich (CHAMPO) - Oct 13 - Lge Cup
Stoke (PL) - Dec 13 12 - Lge Cup
Swans (PL) - Jan 14 - FA Cup
Sunderland (PL) - Jan 14 - Lge Cup
Sunderland (PL) - Feb 14 - Lge Cup - Mandatory 2nd leg
So it's 9 games, up to Norwich, but 13 if you thought Norwich were in the Prem. Grimey run though. This was quickly followed by the likes of MK Dons, Yeovil, Cambridge and PNE