SCL-PPT operates between 3 and 5 days a week (varies seasonally). The IPC-PPT sector is considered to be trans-Pacific, so it is a valid routing, but you have to open-jaw out of PPT at your own expense. So routing SCL-PPT//AKL-SYD is valid, for example, however it might be cheaper to route SCL-AKL-SYD and buy a separate AKL-PPT-AKL ticket.