Can someone help me understand how someone farther down on the standby (ordered) list would clear for a seat assignment before those 'ahead' of them in the displayed standby list? I read the wiki and assume all these codes are behind the scenes and drive what we would see displayed at the gate - the numbered standby pax list.

I tweeted AA who responded "The list is not necessarily in order as there are different types of standby" but then what is the purpose of displaying the list order?

The most recent occasion this occurred was Thurs at ORD - Gate agents cleared #6 before anyone else (I was #1 ), and they began boarding the flight.