"[I]f a plan accepts an invalid rollover contribution, the contribution will be treated ... as if it were a valid rollover contribution if [two conditions are met, the first of which is that,] when accepting the amount from the employee as a rollover contribution, the plan administrator for the receiving plan must reasonably conclude that the contribution is a valid rollover contribution.... [In Situation 1 of this revenue ruling,] it is reasonable for the plan administrator for [the receiving] Plan M to conclude that [the distributing] Plan O is intended to be a qualified plan [because the administrator of Plan M had accessed the EFAST2 database maintained by the DOL at www.efast.dol.gov and determined that line 8a of the most recently filed Form 5500 for Plan O did not contain code 3C, which would have indicated that the plan was not intended to be qualified under Code section 401, 403, or 408]."