(a) An employee's entitlement to impairment income benefits begins on the day after the date the employee reaches maximum medical improvement and ends on the earlier of:
(1) the date of expiration of a period computed at the rate of three weeks for each percentage point of impairment; or
(2) the date of the employee's death.
(b) The insurance carrier shall begin to pay impairment income benefits not later than the fifth day after the date on which the insurance carrier receives the doctor's report certifying maximum medical improvement. Impairment income benefits shall be paid for a period based on the impairment rating, unless that rating is disputed under Subsection (c).
(c) If the insurance carrier disputes the impairment rating used under Subsection (a), the carrier shall pay the employee impairment income benefits for a period based on the carrier's reasonable assessment of the correct rating.