I was under the impression that even after introducing solids at 6 months, milk (breast or formula) was still supposed to be a baby's main source of nutrition until they were 1 anyway. Of course there wouldn't be too much nutrition in cows milk, so you would need him to be eating a variety of foods (which can be a difficult task for a 10 month old). The amount of food you specified actually sounded reasonable for his age, also if he is having yoghurt as a meal and milk on his cereal and in his banana then he is having a heap of milk aside from the bottles you are giving him.

but can I ask why you are concerned about him gaining large amounts of weight in the first place? Did you consider that if both your children had the same dip in weight gain at the same age, that maybe it was a natural amount to be gaining, and that you might not need to stress about trying make him gain extra?

Anyway good luck getting the balance right!