As you can see below we have Ticket On Hold as always the starting point (with diff event time) and need to calculate the time diff. with the next following activities that can ONLY be - Ticket in Progress / Ticket - Waiting for Issue / Ticket Resolved (first one to occur after starting activity)

As you can see from the example below we have to calculate 4 time differences:

1) From Start 1 Ticket On Hold to End 1 - Ticket in Process

2) From Start 2 Ticket On Hold to End 2 - Waiting for issue

3) From Start 3 Ticket On Hold to End 3 - Ticket in Process

4) From Start 4 Ticket On Hold to End 4 - Ticket Resolved