I have added 750 RGB Pixelnet channels to my old sequences.
The only "safe" way to do it that I've found is to add them at the bottom of Track 1 (aka, "the Master" track).
That way, they get assigned the proper ID number and can then be dealt with in other Tracks.
Read that as - add them to the Master Track and then leave them (and all the other channels) alone. No moving, no renaming.
Create a Track 2 or Track 3, etc.., and you can do whatever you want as far as moving/renaming/grouping, even deleting from THAT track. The Master Track will hold everything together.