Misty...I think they're talking about the annual SASS Club affiliation fee:
If 100 percent are SASS members in the club, then the club pays no SASS affiliation fee.
If 25 percent of the club members are not SASS members, the club must pay $75 to SASS.
If 50 percent of club members are not SASS members, the club must pay $100.
I'm guessing that "the letter" mentioned above, is the one sent out by Roxy West last August which came with the new SASS club affiliation application form.