Question about switching foods

We are switching from California Natural to Diamond Naturals. We feed 2.5 cups of the Calif Natural a day. In order to have the same amt of kcals we would feed 3 cups of the Diamond Naturals. This IS the amt recommended on the bag and I know that's often considered high but she is not fat in the least (in fact to me she looks thin but dh and the vet both say she looks perfect) so I don't want to cut back her food. So anyway we will be transitioning her over about 9-10 days. How do we do the amounts? Do we give the same amt when it's mostly the Calif Natural and then a little more for the half and half mix and then a little more for when it's mostly the Diamond Naturals? I wish we didn't have to switch but it's impossible to get the Calif Natural on a regular basis here and the cost is pretty high too. It was $45 a bag and I was told shortly after we bought it that the price went up about $5 a bag.

First 2 to 3 days, 3/4 old food, 1/4 new food; next 2 to 3 days half old/half new, next few days 1/4 old, 3/4 new and then you're done.

Right-I know that part. I wasn't sure how much to feed total each day since the old food is 2.5 cups and the new will be 3 cups. I guess it would make sense to feed 2.5 the first 3 days, 2.75 the second 3 days and 3 the last three days. Or maybe I'm micromanaging this too much. LOL.

I think you're micromanaging too much. Just do 2.5 cups and slowly up the amount after the switch. By the way, I never go by bag guidelines. I'd be poor if I did that!

Just keep some canned pumpkin handy and you should be fine

Thanks! I know most don't go by the bag. Our intention was to start with the bag amount and then adjust as needed but she is staying the right size so we stuck with it. I was actually disappointed because I thought that maybe we could save some $$ by feeding less. lol. She is out with dh all the time and running around (he farms and she is bringing him toys to throw all day) so maybe that is keeping her slim and trim.