Seems like you've got it figured out Gardner.
If you measure the active cone area the difference is quite a bit smaller
I wondered about that, but I was too lazy to figure out actual cone size.
Even if the M22 had a lot more cone area, that wouldn't lead to more volume unless it had correspondingly higher power handling (I think).
Looking at the M60 it dosn't have the ability to handle a huge amount of power either.
I wonder how the ability to produce a wider range of sound at a given volume affects our perception of loudness? Probably not at all.