Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

I can nudge the FTP up a bit more which will bring the TSS down, but it feels like vanity (if you see what I mean), without having done a test to back it up.

If you can do rides that are .9 IF then there's no reason you can't do a proper FTP test.