It's possible he developed, but it wasn't enough to bump it to the next number. So looking at control, maybe when he went from 75 to 76, it was actually 75.2 to 75.7. Then the next cycle he went from 75.7 to 76.3, but it still shows 76.
But I don't see anything too crazy there. He hasn't pitched during that period, so slower progression should be expected.