The CurrentGame folder is a temporary holding place for the save being played. A copy of your saved game gets moved there when you load it up. It stays static while you play. When you do a Save or Save As, that's when it gets updated from what is running in RAM as part of the Save or Save As procedure. When you Quit, it gets emptied out again. It has nothing (directly) to do with sims' memories and you aren't supposed to be copying and pasting anything to or from it. In fact, you're supposed to ignore it entirely unless your game crashes and a copy of the most recent save gets stuck in there, then it's okay to just empty it out (delete the stale copy).
It is not designed to continuously update itself throughout play. If it did, the game would move extremely slowly with all that hard drive read/write access constantly taking place.
In other words, if you play for let's say six hours without saving, then yes the contents of CurrentGame should be exactly the same at the end of those six hours as they were in the beginning.