I have been connecting through DTW (most common hub connection for me) and on several occassions there have been 52 or 54 elites on the list for 2-3 FC seats.

You probably have a lot of DCA connecting/originating pax already on the standby list, plus a historical record of many last minute paid fares out of DCA, so it would seem very possible for a larger number of seats to be held back, and then it is also likely that many of the elite pax on the list wouldn't get the upgrade.

On other routes with lower historical last minute paid walk up tickets sold (yield mgmt) you would probably clear your upgrade much earlier.

RC