I've been looking at the new changes to Caesar and hearing a lot about the FEA Tools program. I had a question regarding how Caesar 2 calculates the SIFs in the new 2017 version 9.0. Does CAESAR II use the calculations from B31J or STP-PT-073 to calculate SIFs?

I'm trying to determine if I would be justified in purchasing the 2 standards in order to improve my stress analysis practices before looking at bringing up FEA Tools with my company.