Good news all around!
Glad to see that you stuck with the 1u>200 even though he was right on the borderline at 206. When my vet drew a line in the sand, I stuck to it, even when I was tempted to say "but it's so close to the line, maybe I'll shoot lower?"
As for the weight loss. The best thing I can advise is to pay attention to how many calories Beau is eating. The lower carb canned tends to also be lower in calories. He could be eating well, but the food is now better for him, so he might need to eat more to maintain weight.
My vet told me last visit to see if I could get a little weight off of Bob, so I put him on a 225-250 calorie-per-day diet. At 14 lbs, he should get 280 to maintain his weight. Three weeks at the reduced cals, and he lost 7 oz. This visit he was at 14.1 vs. 14.5 so everybody's happy. 250 calories is 2 cans of FF plus some, depending on which flavors.
On peeing. Bob announces to the world in general whenever he's used the litter box. Like he's telling me "Okay, I'm done, come scoop it!". He's very particular about a clean box. Unfortunately, he doesn't say anything on the way in, so catching him peeing is a big challenge. Usually, I have to see him on his way to the box to catch it while it's happening.
Carl in SC