If a party to a deed of trust, executed after July 1, 1971, desires to charge an assumption fee for a change in parties, the amount of such charge must be clearly set forth in the deed of trust at the time of execution. Without limiting or prohibiting any other method by which the amount of the charge may be clearly set forth in the deed of trust, the charge may be set forth as:

1.  A fixed sum;

2.  A percentage of the amount secured by the deed of trust and remaining unpaid at the time of assumption; or

3.  The lesser of, the greater of or some combination of the amounts determined by subsections 1 and 2.