Sections 401.10 and 401.11 do not abrogate, rescind, preclude, or otherwise affect any separate settlement agreement entered into prior to the effective date of those sections between a county and an intercounty pipeline right-of-way taxpayer concerning the subject matter of Sections 401.10 and 401.11. In the event of a conflict between any settlement agreement and the provisions of Sections 401.10 and 401.11, the settlement agreement shall control.