How much formula is in each bottle i.e. what is the total amount your lo takes?
I know in the UK it is recommended to have about a pint (20 ounces/500-600mls) a day from the age of 6 months so if your lo is having quite a bit more than that it can affect their appetite for solids as they fill up on milk.
My dd had only 2 bottles a day (morning and evening) at that age but they were full bottles so she could maintain her daily intake - along with milk on cereal, yoghurt, cheese, etc
I would probably try to cut down the milk a bit to see if that improves your lo's appetite for solids.
Seona