Metal And Acrylic Do Not Appear Behind The Scenes

Hi, I'm a noob just trying out this site to see if there is value in uploading. I've uploaded a test image but only had options to apply mark up to prints, greetings cards, and iphone cases.
I notice the image sale page shows options for metal and acrylic, but I cannot find anywhere that lets me set my choice of mark-up for these. I've looked in the forums already and it doesn't seem that anyone else has asked this question before so please don't shoot me down.

Is it because my image is too small so FAA take 100% from the printing of metal or acrylic or is it just that we get a set rate for these print types or because they just add my chosen mark up from the print size list?