Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
AA will charge an additional 37,500 miles for a one-way in Coach between IPC and SCL, or 50,000 miles for a one-way in Business. BA Avios would provide much better value for IPC-SCL.
Since you're trying to get from SCL to LAX, have you checked award availability for LAN's SCL-LAX flight?
Also, note that LAN provides seasonal service between IPC and LIM. And an AA award from LIM to LAX will cost fewer miles than an AA award from SCL to LAX.