not to be a know it all...

but hazels dr was concerned she dropped from the 25th to 18th percentile in weight and wants me to start giving her formula once a day... what?! why suggest formula as the only option?  any of you know i have a chubby little girl.  so i researched and kellymom along with other websites say drs freak out at 6 and 9 months when the percentiles drop in breastfed babies but its normal and they are using charts based on formula fed babies.  so WHO or CDC (whatever that means) recommends using this chart as of recently and im looking and hazel is a little above the 50th percentile!!  dr wants me to call monday with the exact amount of milk im producing when pumped (i didnt do it) and start supplementing and come back for a weight check in 2 weeks.  hmmm how do i tell her no without sounding like a know it all?