It's not a deceptive delivery, it's that he has exceptional extension, which results in less time for a hitter to pick up on a pitch, adding 1-2 MPH to his effective velocity, so his 92-93 plays up more like 93-95.
Still needs to sharpen his command and secondary pitches, but we're talking incremental improvements, not a major overhaul. He was lights out in AAA, so his good pitching since his return seems to reflect normal progress.