Holy crap, you're not paying extra for a day. If you payed $5 down, that comes out of the cost of the end price of the game (i.e. $60, $80, or $150, meaning you'll pay, after that $5 down, $55, $75, or $145).
Unless you meant why is it advertised that you'll get in 5/7 days early? It's not. You'll get in UP TO 5/7 days early.
Read mongrels! READ!!