in laws not following me

Roxanne
Everytime my LO stays the night at my in laws they never follow her routine especially about feeding. When baby is with me she sleeps pretty good at night and only eats once a night which is usually between 4-6 am. But everytime she sleeps over there they are feeding her twice between midnight to 6 am. Sometimes it's 1 and 5 am. Or 2 and 6 am. They don't seem to understand that they just have to rock her to sleep or put binky in her and be patient until she falls back asleep. This is my main problem with them and I have talked to her so many times about feeding my baby too much. When they feed her twice a night then they feed her every 3 hours on the dot during the day. So that totals about 7 feedings a day of 5 oz each and that is a lot of formula!!! 
Also, when baby eats in the middle of the night do you guys give full feeding? Say I give 5 oz during the day and when I feed her at night should I just give 3-4 instead of 5 or what?