We have customers who have different bussiness hours even different among fifferent departments. And we need to calculate creation date/time and due date/time from this.

Now we have to do it very complicated way by adding some time using another automation rules and this is not fully functional because you can add only whole hour (using "set ticket start date"). It is importnat for resolution if the ticket created on 4:35 PM has to be solved this day or not acordingly those business hours. And it is different for customer which have for example 7AM to 4PM and different for other with 8AM to 5PM. 

Thanks