Supplementing with one formula feed before bed?

My baby is 5 weeks old and primarily fed with an occasional bottle of formula (to this point she has had *maybe* 4 or 5 2oz bottle of formula). 2 nights this past week I gave her two ounces of formula before feeding from the and putting her to bed. I am wanting to feed her 2 ounces each night before offering the but am wondering if anyone has tried this and had any problems because of it. I'm not worried about nipple confusion as she goes back to the with no problem after having a bottle or her pacifier and she has her pacifier daily. I will still be feeding for every other feeding and even after giving her the bottle at night so I doubt it will mess with my supply. For those that have done this how did it work out for you?