Thanks for the tip, indeed a round-trip ticket in Y is only $390 when booked through LAN chile, as opposed to ~$450 on LAN US/ kayak. I want to go one-way, however, and continue to PPT and back to LAX/SFO. One way price is almost the same as roundtrip ($370). Would be great to burn 12.5k BA miles instead of $370...I might try calling and see if any agents know what a long sell is.