According to an email I got from AA when I complained about miles not posting on LAN, I was told that domestic flights in Chile do not accure miles in L.
I did however get miles for IPC-SCL in L, so I will recheck this when I can access my mail.
[Edit]:
It seems as IPC-SCL is considered international, I quote the mail I received:
Our agreement with LAN excludes mileage credit for flights wholly within Chile on Economy class fares G, L, M, N, O, Q, S, V and flights wholly within Peru on Economy class fares N, O, G, Q. We are sorry to disappoint you.