SHR and SSR I did measure the same om the scope. SSR is faster in latency because the the pulse is 1.2 sec shorter on center but even about 1.4 sec on one outer edge.

NOR looks like the analog servo mode but can be very tricky with older servo's. Also SHR is searching the limits of digital servo's which normally are specified up to 333Hz. I wonder if you can test UR from the Futaba 10PX (with latest firmware), I think it is a 1000Hz SR (SR is normally 833Hz)