|(a) The certifications and assignments that may become final are: (1) The first valid certification of MMI and/or IR assigned or determination of no impairment; (2) The first valid assignment of IR after the expiration of 104 weeks from the date income benefits begin to accrue or the expiration date of any extension under Section 408.104, if the employee has not been certified as having reached MMI; or (3) The first valid subsequent certification of MMI and/or assignment of an IR or determination of no impairment received after the date a certification of MMI and/or assignment of an IR or determination of no impairment is overturned, modified or withdrawn by agreement of the parties or by a final decision of the commission or a court. (4) A designated doctor may provide multiple IRs if there is a dispute over extent of injury. Whichever rating from the designated doctor applies to the compensable injury once an extent of injury (EOI) dispute has been resolved may become final if not disputed. An EOI dispute does not constitute a dispute of the MMI/IR for purposes of finality under this subsection. (b) A first MMI/IR certification must be disputed within 90 days of delivery of written notice through verifiable means, including IRs related to EOI disputes. The notice must contain a copy of a valid Form TWCC 69, Report of Medical Evaluation, as described in subsection (c). The 90-day period begins on the day after the written notice is delivered to the party wishing to dispute a certification of MMI or an IR assignment, or both. The 90-day period may not be extended. (1) Only an insurance carrier, an injured employee, or an injured employee's attorney or employee representative under 150.3(a) may dispute a first certification of MMI or assigned IR under §141.1 (related to Requesting and Setting a Benefit Review Conference) or by requesting the appointment of a designated doctor, if one has not been appointed. (2) Use of the TWCC 69's non-concurrence section is not a prescribed form and manner for a dispute. (3) A dispute may not be revoked or withdrawn to allow the first valid certification of MMI and/or the first valid assignment of IR to become final except by agreement of the parties. (4) The first certification of maximum medical improvement and/or impairment rating may be disputed after the 90-day period as provided in §408.123(e) of the Texas Labor Code. (c) A certification of MMI and/or IR assigned as described in subsection (a) must be on a Form TWCC 69, Report of Medical Evaluation. The certification on the Form TWCC 69 is valid if: (1) There is an MMI date that is not prospective; (2) There is an impairment determination of either no impairment or a percentage impairment rating assigned; and (3) There is the signature of the certifying doctor who is authorized by the Commission under §130.1(a) to make the assigned impairment determination. (d) This section applies only to those claims with initial MMI/IR certifications made on or after June 18, 2003.