You must be kidding...? No?
If Windows is willing to change what it has stored this time, because you entered something different, doesn't it make sense that Windows will offer to change it again when you enter yet a different/past password? Windows didn't inform you that the password was now etched in stone and could never be changed.
You can also over-rule the auto complete password Windows plugs in for you by entering what you want and then have Windows ignore the change, (or accept it for use next time).
Your own experience, as you have described it, is self-evident that Windows is nicer to you than you give it credit for.