Elf uses a majority PAO based oil for all it's F1 and other racing cars. Their 2 stroke oils are Ester based. What makes one better suited than the other for each application?

Is it the fuel they run? It's been discussed numerous times about great Esters are. I'm curious as to why one would use one over the other?

http://www.silkolene.com/productlist.asp?SECTION_OBJ_ID=25245

Silkolene are bike orientated but also F1. Castor with esters are still being used in Bike oils. The car oils are at least 20% ester. The F1 0W20 oil, which I gather is used off the shelf, is about 2 x price but they probably use similar ester content in all synth oils.