I read it twice and agreed with you but then as I was about to close this window and ended up arguing with myself until I figured it out.
It meant he has collected money on more sales that he would not have had. Nope.
That he is making more now then the first day of sales. Nope.
GOT IT! He sold 100 copies on the first day of sales and has now sold 300 copies. In other words more people are getting the game, THAT'S the significant increase not money, the one thing many of us would use to judge its success