I've tried many formulas (having formula fed all 3 of my kids) but just a thought - she might be like my DD1 who was on 2 hourly feeds for about the first 4 months. She would get hungry really quickly, but only drink about 50-60mls - so she definitely didn't go by the guide on the side of the tin.

Quite a comparison to my DS (who is older) who was a 4 hourly feeder from the get go - then I get this strange little baby who wanted feeding more often! lol.. I just went with the flow, so you could just try it for a bit and see how she goes?