Is bad bottle latch causing our problems

[kleeen]

Dd is 17 weeks and ff. she frequently has green poo and painful gas, occasional puking is seemingly always hungry.

She was exclusively bf until 12 weeks, when I went back to work ( I'm in US ). at that point I planned to combination feed her. She has always been quite a hungry baby, and has gained weight like a champion. Since day one she was very refluxy, with lots of spit up and lots of painful gas. We immediately had her checked for tongue tie, as my DS had it, but several doctors said she didn't have it, and it really doesn't look like that is the problem.
Once we started giving her formula from the bottle, her tummy issues decreased significantly. No more screaming after every feed, so I ended up quitting bf as she was so much happier ff.

However lately her tummy issues are coming back, and I realized that her bottle latch is incredibly weak. Could this be causing her to have bad gas and green poo? How do I improve her bottle latch? We use avent slow nipples. Is there a better kind?