Creating a Fixed Time to Compare Against

Hello Unity friends,

For my game, I have a cooldown timer using this timer setup: http://answers.unity3d.com/questions/222109/making-a-timer.html

I would like to know if it is possible to take the difference of the times and subtract it by a fixed timer ( 1 hour ) to get the difference of that. This would serve as a countdown timer until the next bonus is ready and would update within the Update() function.

I can't figure out how to create that fixed timer though, I have been trying to work with TimeSpan:

TimeSpan difference = currentDate.Subtract(oldDate); print ("Difference: " + difference); TimeSpan _time = difference; _time.Hours = 1;