Good observation, @audition_audio. Just one of the things that makes the RM-200 as unique as it is. And he gets 100 watts out of a pair of KT-88’s not by driving them hard (which of course shortens their life, something Modjeski was very much opposed to), but by creative engineering. How he did it can be discovered with a little research.
Modjeski often said he only introduced a new amplifier when he had something new to offer, not just to fill a market need. He gave talks at two or three of The Burning Amp Festivals in San Francisco, sharing the stage with Nelson Pass, one of the few of his contemporaries he held in high regard. Those talks were videotaped, and may be found on YouTube. Essential viewing!