(a) An operator may impose a reasonable late fee, as defined in Kan. Stat. Ann. § 58-814, and amendments thereto, for each month an occupant does not pay rent when it is due, in an amount not to exceed $20 per month or 20% of the monthly rental amount, whichever is greater, for each late rental payment. An operator may set a late fee at a rate other than the rate provided for in this section if it is reasonable. The operator has the burden of proving that a higher late fee is reasonable.

(b) Any late fee charged by the operator shall be stated in the rental agreement. No late fee shall be collected unless it is provided for in the rental agreement, as defined in Kan. Stat. Ann. § 58-814, and amendments thereto, or in an addendum to the rental agreement.

(c) The operator may recover all reasonable rent collection and lien enforcement expenses from the occupant in addition to any late fees imposed.

(d) This section shall be part of and supplemental to the self-service storage act.