If the end time and the timezone of the HOP are always the same, you can use a simple formula for this.
So, if your HOP ends every night at 18h you can use the following:
$(AddWorkingDays("8 to 6",
AddHours(-6, EndOfDay(0, CurrentDateTime(), "Europe/Brussels")))))
So I add 1 working days according to a HOP called 8 to 6. Normally this takes the identical time as the currentdatetime on the next business day. In your case you want END of business day so you need to add an extra
parameter to the addworkingdays function which is the end time of the current day. In my example this is 18h, so i just take endofday - 6 hours.
This function always gives you next business days 18h.
Looks good, but where do I have to apply this formula in an Escalation Schedule, I see only entries for fixed number of days, hours and minutes