1. An inspection fee at the rate of twenty cents per ton [907.18 kilograms] is required for all commercial feed distributed in this state. The minimum fee payable under this section is ten dollars.
2. Subsection 1 does not apply if:
a. The fee was paid earlier in the year by another person;
b. The commercial feed is to be used in the manufacturing of a registered commercial feed;
c. The feed is a customer-formula feed and the fee has been paid on the commercial feeds used as ingredients; or d. The manufacturer produces only customer-formula feed.