I have a few links on the topic of group IIIs that I have not posted on this forum.
My opinion is that group IIIs when used in engine oil blending are best left for 0W20, 5W20, and 0W30.
The 0W40s and 5W40s likely perform about the same whether group III or PAO.
The PAOs would be the best for 15W50s and higher, as group III base oils are very light.
I always thought that group IIIs spelt trouble for the specialized lubricant industry.
Interesting, 20,000 hours to 2.0 TAN for the turbine oils.
8,000 hours is one year of continous service.
The stability of those turbine oils make it ideal for motorcycle suspension fluids at $2.50 a litre for Shell and other brands of Turbine 32, or synthetic compressor fluids at twice that price.
(MX forks have to be cut down to ISO 15-27ish with an R+O 10)