From my experience, I found that DS was starting to get ready to transition to 3 bottles at around that age, both because of how his naps were, but also because he was able to go longer and longer between feeds. Plus, like you mentioned, they start eating more solids (which is what you want going into the beginning of the 2nd year).
It could be that if you get her to 3 bottles a day, she might drink more milk/formula. It looks like she's doing ~20 oz right now, so maybe trying the 3 feeds will help pick it back up to ~24. My DS was doing ~24 then (still does now, but just eats more
). But, if she's happy, eating and gaining weight well, then it's probably not an issue. All LOs are different.
Anyways, hope that's not too rambling!
Here are some links that really helped me out, that might help you, too
http://babywhispererforums.com/index.php?topic=67569.0http://babywhispererforums.com/index.php?topic=67398.0http://babywhispererforums.com/index.php?topic=67403.0HTH!
