A couple of additions to the Rev-Up page that I recently discovered first-hand.

The Rev-up can be confirmed, for elites, starting 24 hours prior to your FIRST segment on the itinerary. I.e., if you are connecting via EWR, IAH or HNL you will have an advantage in snagging the upgrade.

Rev-ups do NOT show as upgrades on the PDA website.

One question I have that was not resolved by this first-hand experience: Will the Rev-up fee allow an upgrade of the domestic connecting flight, subject to availability (in Z class)? In this case, the passengers (both Silvers) cleared EUA at about 24 1/2 hrs before departure on the connecting flight into IAH, so it was a moot point for this trip.