((a)) Nothing in this chapter shall supersede, nullify or diminish any Federal or State law (including any local law or ordinance), contract, agreement, policy, plan, practice, or other matter that establishes a right or benefit that is more beneficial to, or is in addition to, a right or benefit provided for such person in this chapter.

((b)) This chapter supersedes any State law (including any local law or ordinance), contract, agreement, policy, plan, practice, or other matter that reduces, limits, or eliminates in any manner any right or benefit provided by this chapter, including the establishment of additional prerequisites to the exercise of any such right or the receipt of any such benefit.