hmmm - impossible to "know", but I'd say if his mood turned after his feed, and there aren't other feeding issues it's at least worth a try, right? What's 20 minutes really? Is he always grumpy after that nap regardless of nap length? I don't remember, but how is night sleep - could he still be OT and adjusting to all this - it seems that it's really improved quite a bit now, so maybe not. Do you chart his feeds - can you look at how long they are and see if he takes a shorter one before that and maybe is waking hungry, or, is the pattern of wake, then eat getting established and he is expecting a feed when he wakes? Sometimes my LO is even impatient through diaper change at WU.
When he got up from third nap, you said he had eaten 1hr 15m prior, so do you then hold off 1 hr 45m to get to 3h - you can't because A is only 1h25 right - or is that when you cluster feed? Just curious. You know what else I have wondered - is the 3 hours from beginning of feed to beginning of feed or end of last feed to beginning of next - not that it matters - I really don't think it does - but that's 20 minutes difference right there...
In any case, since our EASY is always shifting, I just feed when she wakes - I have to keep things simple and manageable, and I don't want to spend her brief awake periods trying to fend her off - to what end? It's hard enough to stay ahead of, entertain, and distract dd1! Plus, dd1 is a bit sensitive to the crying, and if dd2 is content, we all can get along and to her next nap much more happily. It seems that when dd2 is vocally needing my attention, dd1 also suddenly needs me for a variety of things - kwim? For us, I'm happy with anything after 2h30, but I'll feed at a WU regardless provided I'm not trying to get her back down as I don't want to feed to sleep. Also, since I feed at WU, it makes things easier as I don't get part way through something else and then have to stop to feed, or wonder at every grunt and peep if she is hungry. Remember, just because we want them on a 2.5/3/3.5 hour EASY doesn't mean that they will only be hungry/tired/awake etc at those times - I can't say that hunger is why he is grumpy, but I also can't say that he couldn't be hungry before 3h... Feeding is bonding too - so again, maybe he's getting used to the routine of waking and feeding and "likes" to reconnect that way - dd1 was like this, and as we weaned feeds, we had to replace those times with reading and snuggles - to this day, we read in the AM at WU, at nap WU and at BT, and at these times, dd1 gets to be in my lap. HTH! Things really are coming together for his sleep though overall - so great! Curious to see if that third nap will extend on it's own, if he needs shorter A time as the day goes on (though I don't think so - I think OT naps end before that and unhappily in general), or if he just needs the hour there... We are still totally all over the place with dd2! Yesterday 3 beautiful 1.5-2h naps and a 1h CN, today, a capped 2h first nap followed by rubbish the rest of the day - a 30m in the pack on a walk, a 45m in the crib after one was skipped entirely and A was shortened, refused CN despite for sure being tired, having another shortened A, and seeming like she wanted to and was going to go down during WD - and then ended up with almost 3h awake before BT (except fell asleep on DH after EBM bottle during burping for about 20m - I guess that could be the CN - better than nothing!)...