I have no idea why he has so much formula... Probably a cycle, hes not eating properly so she gives him a bottle to compensate and back again to the not eating because hes full.
I am the mom of soon to be 5 so I know this issue quite well. What I will do is start cutting his amounts at nap to 4 oz then nothing all together and get rid of the snack bottle may have some screaming at naptime for awhile. Funny, he does well at snack since its usually outside while we are in the backyard walking around playing so I give things like rice cakes, pitas etc.
He is basically in the highchair for maybe 5 mins at a time before I remove his tray because he just sits there and looks at the food for the longest time (no matter what I make) then he starts smearing and throwing. Drives me nuts!
I do make him sit in the chair without his tray buckled in. Although to be honest, depends on my patience level, some days I just get him down and put him back in the playroom.
Really wish parents would have their children better prepared for daycare nowadays grrr.