Tex. Insurance Code § 1301.140

(a) An insurer shall credit toward an insured's deductible and annual maximum out-of-pocket expenses an amount the insured pays directly to any physician or health care provider for a medically necessary covered medical or health care service or supply if a claim for the service or supply is not submitted to the insurer and the amount paid by the insured to the physician or health care provider is less than the average discounted rate for the service or supply paid to an equivalently licensed or authorized preferred provider under the insured's preferred provider benefit plan.

(b) An insurer shall:

(1) establish a procedure by which an insured may claim a credit under Subsection (a); and

(2) identify documentation necessary to support a claim for a credit under Subsection (a).

(c) Information about the procedure and documentation described by Subsection (b) must be readily accessible to an insured on the insurer's Internet website.