I agree with jessmom...
My little guy is 11 months as well and I've just pushed his A time in the am to start his first nap at 11:45. Yesterday he slept for two hours (I usually cap it at 1.5 but decided to quit fighting it!) and then he skipped his PM nap and even though we put him down early to bed 7:30, he still cooed till 7:50 so. Same nap today (he's sleeping but will see what happens length wise. From what I read OT can be so sneaky and subtle to show up!
I would start pushing the A time in the morning... and I always capped the PM nap (weeks ago) to be sure he was up by 4:30 and no later than 4:45 or BT was a disaster and some NW but usually the EW.
he started doing night waking last week so I've dug in my heels and am ready for the bumpy 2-1 ride, how ever long it takes.
Good luck, mommy!