So yer current masterpiece is at a fixed tempo of 79.775bpm.
You decide to put one teeny little pause in there. No prob. Activate tempo track.
BLAM!!! You’ve just set the tempo to 120 and likely screwed up yer project.
Solution: When you activate a Tempo Track for the 1st time in a CPR, Cubase should be smart enough to ‘see’ the current fixed tempo and AUTOMATICALLY alter that ‘ghost’ tempo event at bar 18.104.22.168 to 79.775 (or whatever).
This is another one of those tiny things that shouldn’t require thought or preparation.
It might also be good if a window popped up to ask you, “While yer at it, would you like me to set the Time Base of all tracks to Musical?” or other options which often go along with starting a tempo track.