Hello again,
I have enabled RF Procedure Legs, then rebooted. No luck. The indicated thread you posted above has good information! In my testing tonight, I've found several examples where the RNP's are listed in the charts, but are NOT available for selection in the GTN. BTW, I tested the Garmin simulator also, same result. Another example is the KSAN (San Diego) RNAV RNP Z RW 27 https://skyvector.com/files/tpp/2012/pdf/00373RRZ27.PDF.
Based on what I read in the "GTN 725-750 Pilot's Guide" (Sec 6.9, p190) and other sources, I think that all "Approval Required" (AR) procedures are excluded from the pick list automatically.
6.9 Radius-to-Fix (RF) Approaches
RF legs associated with RNAV RNP 1.0 non-AR (Approval Required) approaches are supported by the GTN in version 6.00, or later, when approved by the installation.
I suspect that any RNAV RNP 1.0 non-AR which doesn't have an RF leg would be included (I don't have an example of that). Ex - the aforementioned KSAN RNAV RNP Z RW 27 has a radius-to-fix from AJADE to SAYAE, therefore the GPS excludes it.
Some of the "lower-fidelity" GPS simulations likely don't check this.
I was thinking of buying the GNS 530 while on sale - could you see if it exhibits the same behavior?
Best Regards,