Distance is rarely in your favor. Occasionally you'll get a good deal on a ticket in a premium cabin on an AA partner that yields more via the distance method, especially if it is a weird routing. Earlier this year I was pricing an AUS-SFO trip in F. AS was cheaper than AA and, if I routed via SEA then I would get more LPs than I would with the higher AA fare. I opted for the nonstop but if I was trying to squeeze every LP out of trip I had an option.

If Distance shows up as the method on an AA ticketed flight it's usually some IRROP that caused the ticket to mismatch with the flights, so they default to distance. And if you are rebooked on another carrier, from AA to BA for example, the LPs on the flight flown will be calculated by distance. As others have said, it's pretty easy to resolve with a phone call to AAdvantage customer service. IME this happens very rarely, so I see no need to audit past postings unless you were rebooked during the trip.