awurtele
I must admit that I am not a fan of your new method of purchasing.
Then use the same method of purchasing used for X3 and every Cakewalk DAW before it, the one-time up front payment option. The biggest different is the more frequent update cycle and the (announced a year in advance) upgrade cycle which is now called a membership.
Just like every version of a Cakewalk DAW before it, when the new version is released, updates to the old version cease. With the new model there is no guessing when your upgrade cycle begins and ends.