can he handle a full A after
Yes, he usually can. You're right, I guess I have my answer there!
Could he be waking earlier than you think?
I don't think so because he's very 'vocal' in that he chats away and makes little noises all the time when he's awake, so I doubt he would lie there and be silent. It actually gets my DH so mad, he wants to sleep in a little more but DS is always making these loud noises!
I'm thinking he's generally slightly OT and that's probably why he's showing tired signs, but not enough to get a good nap? Maybe just a little OT from the slightly earlier wake up? But I'm not too sure how to get him over it, because if I reduce his A times, he short naps, which just makes it worse. Maybe I'll try to put him to bed a touch earlier tonight and see if it helps. I usually do 3.5h from his last nap, or 7PM, whichever is earlier.