Honestly, I would have to check the help regarding this as well, as I've never messed with the Time nodes.

I've just never had a need to as the Trax Editor is much more user friendly in my opinion, than messing with the Time node itself.

Sorry I couldn't help you more, but maybe there is someone that can chime-in that has messed with the Time node itself successfully and can lead you in the direction you want to go