Configure the SLA's to start-over once the priority is changed

Currently, users can configure SLA's based on Priorities, whereby once the priority is changed to another one, the SLA will be using the SLA configurations for the new Priority. However, it will not start-over the counting of time based on the priority. It will be nice if it's possible for the SLA time to start-over as the issue may be assigned to different assingees on different priorities.

A use-case scenario:

1. Issue created with priority Medium, status = New, SLA Resolution time will start based on the Medium priority. The target is 2 hour
2. Issue transitioned through several statuses, 1 hour and 30 minutes elapsed
3. Once the issue priority changed to High, SLA Resolution time start-over counting from the beginning, target is 1 hour (new target), time elapsed = 0
4. Issue transitioned through several statuses, 20 minutes elapsed
5. Issue priority changed to Medium, status = any, 30 minutes is remaining to meet target of the SLA Resolution time for Medium which is 2 hours.