straffo, I'm aware that some of the staff use a simular regime.
In the CT it's either one of two in regulating usage to the "historic" agenda:
1) limit use by limiting available fields
2) or, limit use by something simular to my suggested NPA
Some of the staff gave positive feedback that it works well, but frankly I think the CT is very limited as an 'experiment'. The historic planesets means that the 'usage curve' is already artificially tampered with to a certain extent, and the perkage applied is more of a secondary fail-safe device to intensify the historic aspect. Also, the pilot numbers are too few.
The only way to see if it works or not, is to apply it to an arena and give it an experimental run for about 6 tours. First few tours to accomodate for all the complaints and gripes, and threats to quit AH if it doesn't stop

.. and the real results would be available for analysis after the 4th or 5th tour after it is implemented.
