Yep, i have! On weigh in days when i was still BFing i would quite often do a pre weigh and then do a post weigh to try and get my number as low as possible.. cheating i know! I usually saw a difference of 200-300gs, but DS was having more frequent feeds than your DD, and feeding several times through the night so i am not surprised the number is a little smaller, sounds like your DD was having big feeds less frequently.