Confusion about pricing

On this page it says:

I understood that if you buy it now you get the final version when it was released but one of my friends thought it might mean that if you pay $20 now you might have to pay the difference to get the final version if it ends up higher priced. It might be a good idea to clarify that so people aren’t confused about it.

It also says:

I guess if you actually read the whole page it’s pretty clear but my friend is generally a smart guy and still managed to get confused by skimming so it might happen to others too.

Yup, I’ll clarify this. Cheers