A DME arc can save track miles depending on just where you can join the arc, compared to flying all the way to the aid, conducting a sector entry, flying the outbound leg etc.
Checkboard, nicely put. I also used to have calculations done at different speeds to justify the rule of thumb. Unfortunately they're now somewhere in storage half a world away.
Now, I wonder where I put my whip & handcuffs...
[This message has been edited by Tinstaafl (edited 24 April 2000).]