$18 on Frictional Games Store and only $16 on STEAM

[MulleDK19]

I pre-ordered Amnesia a few days ago for $18 and now I see that it is on Steam for only $16. The issue I have is that if Frictional Games was planning on giving 20% off on Steam why wasn't the same discount applied to their store?

Sure, it's only a few dollars, but I was a tad upset about this as well.
I'm jobless, so that two dollars could eventually mean the difference between whether or not I get something else I decide to buy, like another of their games or something.

Are you kidding me?!? 2 dollars? That's like.. 10 kroner, lol.
If you're jobless and 2 dollars make a difference, then why did you buy the game?

I'd have paid $60 for Amnesia and been satisfied.