It seems like one timer running versus many would be generally more efficient. I only have layperson understanding of computer science, but I think that iterating over an array will be faster than finding disparate objects in level and iterating for each.
Economy controller can just constantly run a timer and when new jobs are created, an event assigns them an int that can be incremented from the timers (or decremented, whichever made more sense).
So the data would be something like a map where you have object reference for the job, and an int to measure how long is has been going on. But the jobs themselves dont have to run timers or watch anything on tick.
I can’t for sure say this is better, just adding it as alternate idea.