I have been contemplating this for some time as well. If you were to read the 217+ Handbook available here, (it is also available free if you have bought the 217+ model through RIAC or 3rd party vendor),
section "22.214.171.124 Part Quality Process Grade Factor Questions
" displays the questions and thats where it looks like the quality of the parts go into account but I still dont see how I can compare a JANS and commercial quality level part with 217+. If I were to give the same environmental, thermal and electrical stresses to each of those parts, I would come out with the same FR.
I really hope someone with more in-depth knowledge about this chimes in.