I haven't the unit's schematics right here, but I seem to remember that the 220 has got two pairs of 2SK135/2SJ50's per channel. These devices operate best at a bias current of 100 mA per pair. Surely you won't harm your amp when biasing them cold at 100 mA all together (if I understand you right), but you might want to check for crossover distortion.
Best regards!
Best regards!