Baby different at sitters

My MIL watches our baby during the week while we work. I've been back to work for 3 weeks. and it seems like my baby is a totally different baby than she is at home. And not just a normal different, in my opinion. I assumed she'd have adjustment issues and what not. I almost wonder if what my MIL says is her way of getting what she wants?? My MIL has been saying almost every dsy that our LO is starving during the day and she insists that I up her ounces. Baby has been consistently eating 3-4oz at a time, and usually more than 4oz makes her spit up. I started preparing 4.5oz just to shut her up, and supposedly this isn't enough either. My MIL insists she needs 5oz. But my LO rarely eats more than 4oz when she's with me/my SO. The catch is, there's ALWAYS 1 extra serving of powder in the container when I pick baby up. So what's the deal?

My MIL also insists that she needs destin because our LO's butt gets red...yet she doesn't have diaper rash and it's never red when I change her before we head home. She knows how sensitive her skin is and that vaseline is all she can handle. And she has vaseline in her diaper bag.

These are just 2 examples, but there's more. I've tried to help my MIL by telling her what our baby is normally like, but all she says is "hmm...I don't know." I told her baby is nothing like what she claims when she's with us, so I don't know what else to tell her.