My recollection is that the Insider Fares mentioned by Valveking are only available if the entire fare is paid with points. This is separate from IAP.
You can call up plat travel services and book these fares with cash, plus a $40 phone ticketing fee. So the additional points value is simply the $40/ticket, meaning that additional points benefit becomes increasingly negligible as the overall cost of the fare increases. Saving $40 on a $100 fare is a big benefit; saving $40 on a $2500 fare is less remarkable.