(a) The maximum maturity or term of an obligation issued or incurred pursuant to this chapter may not exceed the lesser of:
(1) the reasonably expected weighted average useful life of the eligible project as certified by a licensed professional engineer selected by the issuer; or
(2) 50 years from the date of issuance or incurrence of the obligation.
(b) The determination of reasonably expected weighted average useful life of an eligible project made under Subsection (a) may not be contested for any reason.