Ok, here it is from the manual, hot off the editing process:
Instead of specifying a time of execution, an order can specify a waiting period, which will delay the implementation of the new order for a pre-determined period.
Does this mean I can give a second order with a short waiting period, and it will be executed after the first order is done, plus that waiting period? That's what it sounds like.
Real life: This was in a training exercise, but once we had the assistant division commander using our brigade tactical operations center to command the division after the division tactical operations center was "knocked out". At one point he ordered the entire division to make a 90 degree turn to the right. This was considered highly unusual by the sergeant in charge of brigade operations, and it took considerable planning and organization. I got to see first-hand that "There is nothing so much like God on earth as a general on a battlefield."
You might want to keep your plans simple. If you get to a waypoint and there are enemy there, it's possible to lose an entire corps. Keep the turns somewhat less than 90 degrees.
Hook