It is certainly not used at the coal face although I've heard VA (that bastion of ingoring industry standards and practices such as not favoring FIMs from their partner airlines on the totally mistaken belief it costs them money) use 'OA' for other airline. Not an abbreviation used in any other airline I've seen, precisely because when talking about FIMs, why use something that can be confused with an airline IATA code.

I've never heard it used (OAL) but the bean counter story sounds right, they live in their own world.

One popped their head up on an Ansett OTP call one morning after several flights had been delayed due to dupe seating and asked "Why weren't the dupe seats picked up before the aircraft left the hangar???".

Stunned silence ensued shortly after which someone on the call said "I think we'll take that question off line".

Frightening even back then that people were being put in positions with absolutely no idea what they were talking about.