This is kind of a combination of what we had in the latest beta and what we have now.

In 1.01/1.02 PJI delay a ship from jumping by like 25 seconds or so.
In beta 4, the PJI made it so enemies cannot jump farer into your territory at all.

The following is a kind of combination of them both:
if the enemy is jumping from a system that you own that has a PJI into another one of your systems (the second system does not require a PJI), the delay would be 60-80 seconds, otherwise if his jumping from your system with a PJI to one not owned by yourself/maybe not owned by allie? (enemy retreating away) the delay would be 30-40 seconds.

this will give time for your fleets to kill a lot more than currently possible and easily catch up to fleet going deep into your territory, at the same time doesnt deny the enemy from reaching a system deep within your empire without destroying the PJI's.

It should make PJI's the main targets in massive fleet battles, just incase the enemy might wanna retreat (for caps 30-40 seconds just getting prepared to phase can usually mean death if they are already on the run).

the numbers can be modified(+/-) for balance purposes.