Hmmn no, this is not correct. That is not how the selection process works. DOS does not go down any standby list of already chosen AND notified selectees.
Yes the DOS typically selects well over 55,000 in the initial selection. However, in very rare instances, if it looks like the set aside DV (which could be 50,000 and not 55,000, as a matter of fact because of the NACARA Program) will not be used up in a particular FY, the DOS may select additional applicants later in the FY. This is why the Entrant Status Check page (website where applicants check their entries) tells those not initially selected to hold on to their confirmation number until the end of the FY and check again. The DOS is not going down any list of already chosen and already notified selectees in this case.