Ben, at 10 months, is taking 4 bottles a day and a total of 24 - 26 (US) ounces of formula per day, in addition to three solid meals, and a snack, if req'd. Now, he's a big boy, so he's always had a big appetite... when we started solids he was taking 32 ounces/day.
Ben's paed said he should gradually reduce his formula intake from the time we started solid food (~6 months) until 12 months, at which point she said he should be taking 20-24 ounces. Then I guess we can think about replacing that formula with homo milk.
Anyway, I'm just curious how much formula your little ones are taking. Not really trying to compare, just being nosy.