((a)) ** .—** Except as provided in subsection (b), an amount withdrawn from an account under this chapter shall be treated as withdrawn on a first-in-first-out basis.

((b)) ** .—** An amount withdrawn from an account under this chapter shall be treated as withdrawn on a last-in-first-out basis if it is—

((1)) a nonqualified withdrawal for research, development, and design expenses incident to new and advanced vessel design, machinery, and equipment; or

((2)) an amount treated as a nonqualified withdrawal under .