A person who is receiving the exemption contained in RCW 84.36.381 through 84.36.389 is exempt from any legal obligation to pay a portion of the benefit charge imposed under this chapter as follows:
(1) A person who meets the income limitation contained in RCW 84.36.381(5)(a) and does not meet the income limitation contained in RCW 84.36.381(5)(b) (i) or (ii) is exempt from twenty-five percent of the charge;
(2) A person who meets the income limitation contained in RCW 84.36.381(5)(b)(i) is exempt from fifty percent of the charge; and
(3) A person who meets the income limitation contained in RCW 84.36.381(5)(b)(ii) shall be exempt from seventy-five percent of the charge.