Make Time Limit in app

Hello Users,
I am trying to make time limit for users to use it.
I am using Deep Host’s Countdown Extension to make countdown.
I used one tiny db to save time when app is not in use.
When screen1 initialize, tiny db call store data and if it is less than 60 sec, I multiple with 1000 to convert it into milliseconds but if it greater than 60 sec or 1 min, I multiple with 60000 to convert it into milliseconds, but it makes it more than 4 hrs.
I searched community and find below post :

But this post not help me to solve problem.

Here’s the blocks, I used to do this.