Not sure. It could be tighter ab muscles and better posture. Certainly, it's not reflected on the Tanita or the calipers.
I think the changes in the size of the muscles is just variability. It's too small to say with certainty, although I do believe my arms are getting a bit larger.
I would be happy with staying the same and stripping the fat. Really, if I could lose the fat, I think the muscularity would pop back pretty quickly. Then I would need to work hard to get in shape like JP and Johnka (something I would have to work VERY hard to do). I just want to lose the fat and would be willing to lose some LBM to do it.
BTW, the calf was a decrease. Kinda bummed about that -that is where I am pretty puny (my upper arms are bigger than my calves!).