Axiom is interested in creating satisfied customers rather than making quick sales. They will not recommend anything but what they feel is best for the customer.
The size of your listening area will influence that recommendation. If Axiom feels the M22s will be adequate, you can bet they will be. On the other hand that doesn't mean the M60s would be overkill.
I initially purchased the M22s. They, along with my HSU STF-2 subwoofer, performed just fine in my 11.5' x 18' x 8' room, providing all the clean volume that space required. And, they sounded terrific. However, I felt there was something lacking in the upper (mid) bass range, which, IMHO, had more to do with the limitations of a bookshelf speaker itself, rather than the quality of the speaker. I returned the M22s for the M60s, and was completely satisfied. Many contented M22 owners have not experienced what I did, and have no complaints about them at all.
The M80s can be a little more finicky when it comes to placement in smaller rooms. That may be a factor in Axiom's recommendation.