Hello: It sounds like she is deft. having reflux issues, but in many of our cases, reflux is caused by something, normally milk or soy.
The gas sounds like LI or a milk intolerance.
We never had good experience with LI formula, because my 2 lo's could not handle the actual milk protein.
With Tyler, my 11 month old, he had the WORST gas ever. We ended having to go on an Amino Acid based formula, and now are on Nutramigen, which is hypoallergenic.
We went on Soy formula for a while with (I thought) great results, but it was causing his silent reflux to flare up again and he was in pain all day, not gassy, but very very cranly.
I would try the Lactose free formula, worth a try, but if she is still gassy or in pain, then you may have to try Soy or then a hypoallergenic formula.
After that is no improvement you may have to end up trying a new reflux med, prevacid solutabs or something stronger than what you are giving now.
You are right, we mommy's know best!! The doctor's are not with us in the middle of the night when our baby is screaming.
I would give it a try and see, can't hurt.
Wendy