Probably because Woo has to design to a pre-determined price point. If you want their all out assault, see the WA5.
Jam has no such restrictions, such as worrying about who would buy such a boutique amp, he simply goes with whatever sounds best to his ears, damn the practicality. He's willing to make the effort to get small gains in the amps ability to reproduce music, and fortunately has the talent to do so.
Owning a "stock", maxxed WA6, I can tell you it is no slouch as-is.