Iowa Code § 625.23: Limitations.

If action is commenced and the claim paid off before return day, the amount shall be one-half of the sum above provided, and if it is paid after the return day but before judgment, three-fourths of said sum; but no fee shall be allowed in any case if an action has not been commenced, or expense incurred, nor shall any greater sum be allowed, any agreement in the contract to the contrary notwithstanding.