Almost always points plus pay is more expensive, as it is the purchase fare converted to points using a poor exchange rate; hence varies with supply and demand. Occasionally some sale fare pops up cheaper on points plus pay than classic award ... this is rare (<1% of the time). The ponit of points+pay is that it is always available -- even when rdiciulously expensive. I've seen it go as high as 10x the classic award rate when high-demand exists, so sky is the limit. Conversely it gets cheaper as you pick routes & dates that people aren't buying, for whatever reason.