That was the reasoning for my DD, the solids help keep the milk down. My paed also wanted us to cut milk back to help but I wasn't happy with that one - I was struggling to get her up to 20oz at the time which is the lowest amount they need and she was puking lots of that back up
. With a bit of cereal and meds she upped her milk intake and was much happier. We started DS on solids a bit early because of the reflux too, but it made him worse so we had to stop for a while. You never can tell with refluxers, some do better, some don't.
Lewa - it sounds like her milk intake is good at the moment, just keep an eye that it doesn't reduce at all for the next few months at least. I would also take it really slowly on other foods too, the rice is doing a thickening job but other foods may be more irritating for her.
Laura