I've no doubt at all that you're significantly stronger, but not all of that 40 extra pounds is going to be muscle. You might want to reduce the amount you're eating now so that you don't have to eat at a deficit for so long later.
It's also very difficult to lose fat and gain muscle at the same time, especially if you're not a teenager anymore. Still, congrats on your progress!
I've also changed my diet significantly- I eat way more protein and fat and almost no carbohydrates. I think that has as much to do with my fat loss as the exercise.
Your post doesn't really refute my point anyways, because it's very hard to gain muscle and lose fat at the same time for adults. You're talking about one direction i.e. gaining muscle.