Create a subprocess if X of the specified time has passed

The client needs a solution: If the task is located more than 15 minutes from the date specified in the Schedule or add. field - create the desired subprocess. In this case, it is impossible to change the stage (!) Came up with a solution before this for the 60 minutes condition: https://prnt.sc/wly6gn Where I count the date parameter from the date difference - https://prnt.sc/wly736 And then I create a subprocess - https://prnt.sc/wly7ur , https://prnt.sc/wly824 That is, 3 conditions are met and a subprocess is created. If you set the condition for 15 minutes, then in any case I get the condition that the action "Calculate the difference in the dates of the process, taking into account the coefficient and write in the additional field of the process" is triggered once an hour. But since it takes 15 minutes, I can’t think of it without revision. Perhaps there are solutions? If with refinement, I ask you to give advice and an assessment of how best: 1) Refine the action - Calc