He can try it, however, the subwoofer MultEQ filters have 8x higher resolution than the satellite channels, so room correction in the bass (where it is most needed) will be much better.
Audyssey will not provide correction to the satellite speakers lower than the frequency Audyssey measures as the -3 dB point, so if he changes it lower, your defeating the whole purpose of having Audyssey engaged, might as well not use it then.