Patrik and Magnus at Scuba Supply will take care of you, I've just written them about the issue.
I've never heard any comments one way or another on the ball height on E-M5. The taller version (24224) probably puts the strobe mounting positions a bit more even, and provides a bit more room to operate the clamp. The tops of these small housings can get pretty crowded! Hopefully some other users will chime in here.