It is difficult to explain at first, but easy implement in practice. It provides the GA a sorted list of pax who would accept a VDB if the price is right, and an approximate price they would accept for that VDB given a reasonable revised flight booking with the lowest offer at the top of the list.

The improvement over the existing for the airline is that it helps keep down VDB. The current system encourages pax to wait it out to see how much they can get. For example. under the current system the GA makes an announcement that says "we need 4 volunteers for VDB, and are offering $200 to do it." As a solo pax, I walk up close to the GA, and look around to see if anyone else is biting on that offer. After a few minutes and no takers, the offer gets upped to $400, than $800. Finally at $800 some people start walking towards the GA. Quickly I jump in line and take the GA offer for $800. Now truth be told, I would have taken the $200 offer. But since I could play the game and wait it out for more $$, I did. This happens all the time.

The new system I described avoids that, as you can easily target the lowest bidders at close to their low bid price.