Scurvy,
1. I'll second Claret's comment. We use "Approaching" to tell you "we need the next level you can give us" to stop the friggin autopilot go into capture mode with all the attendant dramas.
2. I've never used "approaching" as a response to "report present level"
3. Please enlighten the masses about how a 100ft (in this case lower) more accurate level call would help any aircrft trying to conduct an instrument approach at say Alice: there is obviously an aircraft in front on the same/similar instrument approach or in the same area and the follower is never going to get visual if I, the one in front, hasn't got visual, being 1000ft lower! If the cloud base is XXXX, the only way an aircraft is going to get Visual is to be at XXXX. It won't matter if they get cleared to XXXX+300 or XXXX+400.
4. "Checking" separation with a lighty? Interesting concept! Wasn't it already assured by the clearance we were operating to?
5. I've never had the pleasure of being Maestro'd. Sounds like great fun...not.
Boofhead,
Yes it does, except that ATC must apparently allow a 400ft (??) buffer on the Transponder readout before assigning the level below or above us. If we give it on the R/T, they can assign it immediately. Sometimes I think they are just reading the paper and want us to remind them when we "left" a level. But they don't realise that I'm onto my first cup of coffee by then and by the time I put it down, put the Inside Sport down and hop on the radio, I'm a couple of thousand feet past when they wanted me to call anyway!