Wait, why does the first line say "Time_Fonts -> Subtract from time_font"? It should be "System->Subtract from time_font".
This means you have two time_font variables - one global variable and one instance variable on Time_Fonts object.
Every 1 second you are changing the instance variable, but you set your text to the global variable (which doesn't change).
You need to decide which one you want to use and delete the other one.