Best way to use 1 countdown time for multiple levels.

I have a game where it uses a set time to complete many levels (this time can be added to if user completes a level).  What is the best way to do this?  I was thinking of just having a parent composer scene and creating the timer in this scene and just doing overlays for each of the levels (levels don’t need to take up whole screen so things like exit, time, score, settings can all be done in the primary scene on the sides).  Would this be the best way, or should I just pass the time as a param and load each level as its own scene?

I see both ways working but I feel like having the levels as overlays would reduce the amount of code needed as well as run smoother.  Thoughts?