This link has a graphic showing how to determine if a dog is carrying too much weight:
How to Tell if Your Dog is Too Fat or Too Thin - Albuquerque VetCo
If you cannot feel the ribs with gentle pressure, that is a sign that he may have a little too much weight on him.
I would cut treats rather than the nutritional food. 3 - 4 of the biscuits daily is a lot, and Cheerios can add up quickly. Plus, the Cheerios have sugar. You can substitute low calories treats like green beans or just use a single piece of kibble as a reward.
I use the kibble as rewards, but I have to watch how many my boys get. They were earning a few too many potty rewards.
