There's nothing "dubious" about correcting a value measured at one CG to the equivalent for a different CG. Indeed, it's REQUIRED that this be done when determining the performance data for an aircraft, which must be shown for the critical (usually most forward) CG. That's the context of the original question - correcting measured data from one reference to another.
It's got nothing to do with trying to analytically correct some theoretical "CLmax" to some other theoretical value. It's to do with the practical question of correcting measured test data.
And, speaking from that same practical point of view, i couldn't care less what the notional CLmax is of an aerofoil, or even of a wing for that matter. What I need to be able to do is present stall speeds in a flight manual, and to do that i need a means of determining that speed, which it is convenient to base on the concept of a maximum lift coefficient, corrected, as required by regulation, to the CG limit.
see AC25-7C, 29.d(5)(d) (on page 131 of the AC) for an "official" description of the correction
Last edited by Mad (Flt) Scientist; 4th Jan 2018 at 16:48.
Reason: Added reference to AC25-7C