How did you calculate that? The release date (first Wednesday in December) of Cubase 10 is actually December 5th, 2018. Just so ye all know when ye need to have ye mon’y saved up.
No one noticed that the next Friday is day 9?.. so 
It’s not based on the day of the week, it’s the dates - 5, 4, 3, 2, 1, 0
So far (well at least before yesterday) the release date corresponded to both the day of the week (i.e. Wednesday) and a decrementing date. No way to tell (until yesterday) which one mattered - assuming it mattered at all and wasn’t just a coincident without any real underlying pattern.