Are condo and HOA fees always due on the first of every month?

In North Carolina, our dues are due the first day of the month, late on the 1st day of the next month. Our Board is telling the homeowners there is a North Carolina law that states we can not collect late fees until the first day of the next month. Is that true? I recently purchased another condo in a different HOA and they start assessing late fees after the 15 of the month. Please advise, thank you.