Originally Posted by RonRicco

But, prior to C2K you also had high and low yellow slips without regard to DOA, partial month move ups (allowed you to hold a line for part of the month) first out on a YS on an X day. This gave you a lot of control over your schedule and the ability to fill up quite easily.

C2K eliminated PMM and restricted YS to DOA, but also introduced the long call window we have now.

I guess beauty is in the eye of the beholder.