A claimant who timely demands appraisal under Insurance Code § 2210.574 or § 2210.5741 may request a supplemental payment on the accepted claim or accepted portion of the claim at any time. A claimant who does not timely demand appraisal may not request a supplemental payment after the deadlines for demanding appraisal under Insurance Code § 2210.574 or § 2210.5741.
28 Tex. Admin. Code § 5.4204