Digital predistortion of bipolar power amplifiers
In the nice theoretical low signal power world of assuming everything is a cubic nonlinearity, it's possible to write a relation between P1dB and P3dB, IP3, ACLR, and other 'limits' on the amplifier performance.

However, at high power, where you want good power added efficiency, and digital predistortion techniques get useful, the shape of the distortion curve becomes very implementation technology dependent, and we discover that these limits are no longer proportional to each other. 

'Perfect' predistortion with a completely stable predictable amplifier technology will of course work to any power within the capability of the amplifier. If a predistortion system is specifying a lower limit, then something other than that is going on. Maybe the predistortion implementation has been designed down to a cost. Maybe the amplifier it's been designed to be used with has unstable distortion levels with small temperature or supply voltage variations.

Remember that if an amplifier is producing a large amount of distortion, and the predistorter a large amount of 'anti-distortion', the resulting output distortion of the system is the small difference between two large quantities, so exquisitely sensitive to small errors in either.