Here's my dogs and calories experience: I put one of my Rottweiler girls on a raw diet because of allergies (couldn't find a single kibble without at least one of the things she tested as sensitive to). I knew how many calories she was getting with kibble and matched it with raw. AND over the next couple of months she steadily gained weight. I had to cut and cut to find the actual amount of raw she needed to maintain a healthy weight.
So here I am again, at last able to put my other Rottie girl on raw (have been feeling guilty about her being on kibble while the other one got the good stuff). It's been 5 months and I had to take her to the vet yesterday. I knew she'd gained some weight, but according to the vet she needs to lose 15 pounds! IMO she only needs to lose 10, but even so....
When I mentioned my experience with the allergy girl, people on this forum theorized that maybe Story was absorbing the raw food calories (and hopefully nutrients) in the raw diet better. If that's true, so is Teagan, but I've always believed a calorie is a calorie whether it comes from junk food or health food.
Anyway, my girls need fewer calories on raw than they did on kibble, so in the OP's shoes, I would only match calories of old diet to new diet as a starting place and afterwards keep an eye on the doggy waistline, adjust accordingly, and obviously do that adjusting quicker than I did.