Hi Steve,
Last January I posted about the RXP530. I also used the F1 GTN750 which recently became incompatible with P3Dv5 following the latest hotfix.
I thought it might help if I confirmed that I'm still churning out IF flight plans as before, but for use in my new RXP GTN750. The only change is in the export destination of the IF plans. The RXP device needs only one file, an IF.gfp exported to C:\ProgramData\Garmin\Trainers\Databases\FPLN
Regards, Jim