(1) The state board of education shall establish a statewide formula for an authorizer oversight fee, which must be calculated as a percentage of the state operating funding distributed to charter schools under RCW 28A.710.220 to each charter school under the jurisdiction of an authorizer, but may not exceed four percent of each charter school's annual funding.

(2) The state board of education may establish a sliding scale for the authorizer oversight fee, with the funding percentage decreasing after the authorizer has achieved a certain threshold, such as after a certain number of years of authorizing or after a certain number of charter schools have been authorized.

(3) The office of the superintendent of public instruction shall deduct the oversight fee from each charter school's distribution under RCW 28A.710.220 and transmit the fee to the appropriate authorizer.

(4) An authorizer must use its oversight fee exclusively for the purpose of fulfilling its duties under RCW 28A.710.100.

(5) An authorizer may provide contracted, fee-based services to charter schools under its jurisdiction that are in addition to the oversight duties under RCW 28A.710.100. An authorizer may not charge more than market rates for the contracted services provided. An authorizer may not require a charter school to purchase contracted services provided by an authorizer. Fees collected by the authorizer under this subsection must be separately accounted for and reported annually to the state board of education.