Why not more on 845 SETs?


As a brand-new owner of a Bel Canto SETi40 int amp,(bought used) I was intrigued to see very little in the fora on the subject of 845 SET amps an A'gon. It seems that this provides the best of both worlds -adequate power to drive most moderately sensitive speakers- 40 Class A SET WPC with SET sound. What is the downside to this approach and why don't more of the SET groupies have higher powered amps, giving them much more latitude in speaker selection? I drive 4 ohm 87 db sensitivity Totem 1 Signatures quite adequately with this amp. Is it beacuse of transformer issues, difficulty in finding adequate designs, size or the feeling that this is not a true "SET sound"?
I would like to hear SET-owners' reasons, if possible.
springbok10
As you go from the standard 845 to the 845B to the 845M the sound gets smoother with more detail and texture in the midrange. The presentation gets darker and more relaxed. It is a matter of preference. I would recommend atleast the 845B. I think the 845C is the same as the metal plate. I could be wrong.
That website shows this tube available, but not the 845M, thats why I am asking. My amps will be delivered by the end of the week, and I am a tube junky, so I wanna get set for some fun rolling. Too bad they do not have M's to ship now.

Thanks
Can anyone answer this question? My Bel Canto SEi40 was working perfectly with stock Chinese 845 tubes (Edicron), but, of course, I tried new tubes - 845Ms - suddenly, the amp programming/control mode went beserk - muted intermittently, and switched itself on spontaneously without touching the standby button - only with the 845Ms!!! Can there possibly be any relationship between the IR sensor of the amp and the 845M tubes????

Then, when original stock tubes were put in, no more erratic "possessed" behavior by the amp!

Any input, other than "don't be insane" - would be appreciated!