To present a hypothetical situation, Myra R----- works at Entity W and enters retirement plan 3. She later transitions to work at Entity T, an entity within the controlled group in which Entity W occurs. Entity T has not endorsed plan 3; she attains normal retirement age while at Entity T. To prevent ambiguity, Myra R----- transitioned from Entity W prior to having attained unequivocal vesting, though with a sufficient balance to thwart ยง 401(a)(31)(B) distributions. Must she receive full vesting while employed at Entity T?