Staff:
Cheapest Y < 8 hours.
Cheapest J > 8 hours.

Management/Exec:
J everywhere.


Hours are based on time traveling not on flight time and require booking of the shortest round-trip time. So flying LHR-MAN via JFK to get into J will result in a chat with your manager.

I personally prefer this policy over previous ones which where based off flight time. In some cases a 4 hour flight can result in a 20hour+ trip time and the J makes sense. In same cases it's just a 5 hour trip and there is just no real good reason.