I believe that PPT can (on occasion and maybe in error) also be part of the SWP: I managed to have it approved that way on an LGLOB34 ticket in 2004 (the originally ticketed itinerary was
SYD-xCHC-ZQN-CHC-xAKL-PPT-IPC-SCL-JFK,PVD-xORD-STL-BOS-xLHR-PRG-LHR-EDI-LHR-MEL-CBR
so PPT must be SWP or else there are too many segments in SWP for a SWP-originating ticket).
This was approved by QF.