Thanks for the clarification - as a follow up to this, there appears then to be a difference between the "waves" system and the standard pre-order system which is evidently used on most games. For example I preordered Forza Horizon 3, it went into my game library, and on the release date, it unlocked. It was ready to play, for everyone who had pre-ordered, no codes needed.Waves is just how the store works - and actually XBL does this historically too - which is why you see threads with people asking if it's here yet on other games. And that wave function (sorry science) is one of the reasons we have fairly nonspecific timing language, which was one more thing piled on here.
Was there a specific reason it was decided to go with the waves system for Halo Wars DE instead of the "normal system" (not sure what it's actually called), that seemingly would have let everyone play at the same time instead of creating questions around why some who have pre-ordered don't have access today?