It is not a typo, but you could submit a rule change...
Most SA helmet shells are larger than M and are not designed for aero.
It would seem that just a raised eyeport would not make a helmet SA. I suspect they are altering a different helmet if it has to be marked SA.
Let us know how your rule change goes...
Good idea Stainless, I not that quick on the draw about asking for rule changes, but there are times when changes would help the folks racing.
Not a different helmet, same one just raised port, maybe a testing thing if you make any changes. I don't manufacture helmets, so I leave it to them to make that call.
I'm sure they are following the regulation that governs the call on the Snell designation.