DX3r framerate setting for use with Castel controllers?

Morning all.

I have recently bought a Spektrum DX3r radio, and I have been playing about with some of the settings that it has. One is called framerate, and this can be set in three positions. 16.5ms, 11ms or 5.5ms.

It does say in the manual that the faster settings are only to be used with digital servos, but it doesn't mention ESCs at all.

Can anyone tell me if it is safe to use the faster framerates with a Castle speed controllers (I have a Mamba25, Mamba Max, and I'll soon be ordering a MMM).

So far I have only dared to try it on the 16.5ms setting, which works well. I don't want to risk damaging something in the ESC by setting it faster though. I do want to use a faster setting though, if it is possible without damage.

Cheers
Andy