2 extra second domains?

On the webpage extras areas, it says “Just when you thought it couldn’t get any better, we’ve upped the ante! If you choose to pay for an extra domain six months in advance, you’ll get TWO extra domains! If you pay one year in advance, you’ll get THREE extra domains! Holey moley!”

I just (a couple of months ago) added a second domain to my account. So does that mean if I had waited I would have gotten a third? and a fourth? Also, are these two for the price of one? How is this working money wise?
I prepaid mine for a full year! I want the extra domain thingy!

Raven Oak