Re: 2nd time around not so easy, he seems to WANT formula!!
I was going to suggest silent reflux or overactive letdown as well. He could very well seem more content after a bottle if either of those were the case, either because the formula doesn't cause the reflux, or there's no letdown with it. It sounds more like a reflux issue to me though than overactive letdown.
Tired mama to Miss Bookworm (9), Mister Tornado (6), Monkey Boy (4), and Little Mischief (almost 2).