For fiscal years 2017, 2018, and 2019, supervision and inspection fees for telecommunications carriers subject to Section 37-2A-10(1), (2), or (4) shall be reduced in three equal installments representing, in total, the difference in fees paid by a carrier in fiscal year 2015 and the amount of fees calculated pursuant to Section 37-2-41 for fiscal year 2015. For fiscal year 2020 and subsequent years, fees for telecommunications carriers subject to Chapter 2A, Title 37 shall be paid pursuant to the formula contained in Section 37-2-41.