The highest one day sales doesn't have to equates to the highest three day sales or the highest seven day sales. Those are three separate numbers that could range all over the place due to the steam of a film, album, etc.
Math, bro.
You could just say "fastest grossing film ever" and it would get the point across just like saying "fastest to 100M, 200M, 300M, 400M".
But movie fans do it all the time so w/e. It just drags on and it's not like anyone actually needs to know "fastest film to gross $300M" or "highest gross on Wednesday night".
Remember when Alan Rickman was supposed to sweep the Oscars and didn't even get a nomination for DH2? Not everyone can be as iconic or as great an actor as Alec Guinness.