(2) A person using a private collection agency to collect a commercial debt owed to the person may add a reasonable fee to the amount of the commercial debt, payable by the debtor, to compensate the person, in whole or in part, for the collection agency fee incurred or to be incurred. A person may not add a fee under this section that:
(a) Exceeds the collection fee of the private collection agency; or
(b) Was not authorized in the agreement or contract creating the commercial debt. [2003 c.66 §2; 2007 c.204 §2]