Hi and welcome to BW. Dont worry about it, I think every mom feels like she is doing everything wrong, especially if its her first baby. I sure did.
Wow, 10oz, my 11 month does not take that much.

Is it possible that he was going trough a growth spurt on the days he wanted more milk? Its usually then that they want more food.
How was he sleeping on the days he wanted more milk, and how was he sleeping before that? Also, how long after the milk feed do you offer the solids?
3 solid meals is a lot at 4 months.
Take a look at this link
http://babywhispererforums.com/index.php?topic=36922.msg238074#msg238074 How about you cut the solids for a few days, see how that goes, if he seems more hungry, how is he sleeping on those days. Then try and give him just breakfast. Like you are introducing solids all over-just a little bit at first. Then a bit more and then more.
Maybe even keep a log of how he`s doing. How much he is eating and how much milk he is taking.
What do you think about that?