What's this 500 ft above the step?
You are under it if at the lower limit, but in it at the altitude given to you by ATC, so is what you are saying, that to be in airspace where the LL is 7500ft you would be at a minimum of 8,000ft IFR? That makes sense if this is what you mean. Have never thought about it being an actual requirement however I guess it's a given.
(the first sentence above sounds aggressive, but it isn't meant to be)
.1 nm is a little bit tongue in cheek, but point being, have never ever been questioned on it. Particularly when getting a clearance, many of us come super close to CTA if not in it by the time the clearance arrives.