The guideline in the UK is to have a minimum of 20oz per day, but this does not have to only include Formula / BM it can include milk in cereals, custards etc, as well as yogurts cheeses.
Our afternoon bottle does not always fit well with our naps, so if naps are a bit weird, we tend to split the bottle in two, and offer 1 before nap and the other after nap, that way she does not wake up mid nap hungry.