I have looked into it and I regret that I discarded my notes.

However, it works like this:

-You choose the maximum mileage from one of four or five levels (eg: 29K, 32K, etc)
-You choose the class of service (Y, J, F - I forget exactly, but I think that only Y is allowed on the shortest maximum mileage option from the first step)
-The price is set accordingly
-Only good on Skyteam metal
-Need to have availability in certain class of service. For example, business tickets must have D bucket availability (I think it is D, but not 100% sure)

If you call DL, ask for the RTW desk. They are very helpful. Report back with corrections to my notes and details concerning miles and costs.