Cindy, Im not the AG but as the former Treasurer of an HOA I've got an answer you aren't going to like, and the answer is yes. The condo fee, date due and penalties for non-payment are specified in the public offering statement, which you agreed to abide buy as a condition of the purchase of the condo. As long as the money is not in the Treasury by the due date the payment is late. Having said that, I encounterred situations with extenuating circumstances and the homeowner could appeal the late fee to the BOD. More often than not, if an honest attempt was made to pay, the BOD would vote to write off the late charge.
I suggest you not waste your time investigating the legality and find out if there's an appeal process to your BOD.