"wisdom" to plug your amp into the wall comes from (IMHO crappy) "power conditioners" that limit current. the PSA regnerator does not limit current and the amp will certainly benefit from it. In most cases the amp will benefit a lot.
However putting 750 watts on a 1000W power supply isn't optimal. sure it will work, but it will run warmer and possible make a little noise. I much prefer to keep load below 50%. I'd buy the PS Audio P20 and plug my amps into it.
I have just upgraded my amp and it pulls more current. I'm now at about 300w on my P10 and I'm thinking of upgrading to the P15.
Of course with amps that pull 600 watts, you are certainly more comfortable than I am with electronics that run warm or even close to hot. that's a lot of power to run continuously, perhaps all day.
Jerry