Hmm - that's interesting, because at the same time of year my car has managed 305@atrw with just a decat and bleed valve, on that exact same RR. No idea what the fly figure was as I don't care.
But, and the reason I mention it, is up at APT's RR one hot summer day my car did 315@atrw, and the 'corrected' fly figure was 350-odd, which is much more likely.
Basically, forget about the fly figure, and concentrate on the wheel one. It's the one pushing the car along after all. Also bear in mind that different RR's (my car was unchanged between runs) will return different results.