BF + formula

Any one doing a combo? I've started supplementing with formula bc I don't pump much at work. So I nurse morning/night. And she takes two 6 oz bottles and a little 3 oz snack bottle. This just seems like a lot of milk in a day LOL. She eats three solid meals with a great appetite and snacks/water. She just turned 11 mo. I guess I just assumed she would want to nurse/bottle less.