In the case of the participation of an individual (or the individual’s parent) in a premium assistance subsidy under this section for qualified employer-sponsored coverage, the State shall provide for payment of all enrollee premiums for enrollment in such coverage and all deductibles, coinsurance, and other cost-sharing obligations for items and services otherwise covered under the State plan under this subchapter (exceeding the amount otherwise permitted under section 1396o of this title or, if applicable, section 1396o–1 of this title). The fact that an individual (or a parent) elects to enroll in qualified employer-sponsored coverage under this section shall not change the individual’s (or parent’s) eligibility for medical assistance under the State plan, except insofar as section 1396a(a)(25) of this title provides that payments for such assistance shall first be made under such coverage.