calling bf experts...

[chibi]

I had to express enough milk for 24 hours as I've had to have an IVU Xray. I figured that 8 oz every 4 hours would be plenty (my dd is nearly 6 months btw) as this is the amount of formula a friend of mine gives her dd who is the same age.

My dd has guzzled the milk, she has taken in at least 15 oz within the last 5 hours.

Normally she feeds every 3 hours-ish from both breasts about 5-10 min per side.

My question is, is she eating this much today as it is easier for her with a bottle? Could she really be eating this much normally? Does she have an insanely fast metabolism, she is a skinny minnie between 9th + 25th centile?

i think she is probably eating as much as she usually does. personally if you can expres that much milk then you have got good milk stores! i can barely express 2 ounces yet i am still breastfeeding! your breasts produce the enough amount that your baby requires.
try and stay on the one breast for the whole feed, then use the other at the next feed. i was told to do this as the first bit of milk is the fore milk which is like a drink then after that comes the fatty milk which is the equivalent to the meal.
you cannot tell about metabolism at this stage as metabolism is linked to muscle mass. she may just be a petite baby and remember that if you/dp are skinny then she has inherited that from you.