Ah, that's a clearer question (and reading back, I see it's what you originally asked). I don't have massive snow experience (actually, none), but since nobody else is answering I'll answer anyway.
I understand that more HP = faster clearing. In concept a BX will do what you're asking (well, not with that particular snow blower), it'll just do it really slowly.
So the depth of snow isn't what controls how big of a machine you need, it's the area that you need to clear, and the time you need to clear it in. Perhaps if you give some idea of what you're clearing and timeframe it'd help people to give answers? I'm guessing it's roads, not driveways, so it's xx miles of road you need to clear each day, and you're running 14-18 hours per day.
It looks to me like you could go M5, M6 or M7 in that HP range. I'm assuming you don't need to trailer it - you're going to drive it from place to place? I think a heavier machine would have more traction in the deeper snow, and perhaps a more comfortable cab. The M5 and M6 are available with the same 111 HP engine, the M6 and M7 can be had with the 131HP engine. There's also the 151 and 171 in the M7, but they both would seem overkill for that particular snow blower.
Do you have the budget to stretch to an M6-131? It would certainly make sure the blower never bogged down, and perhaps give a bit more traction.
Ultimately you either have a specific area that needs to be cleared from 4' of snow in a specific timeframe, someone could comment on what machine you need for that. Or you just want the biggest sensible machine you can get, because a bigger machine will let you do more area, and therefore make more money. Someone can probably comment on when you get to the point of diminishing returns. It seems to me that an M7 would be well over that curve, an M6 probably is as well but like I say, I don't know snow.