Maybe you can contact the seller and ask what they mean by "steamed".
Could be they ironed it with steam? I buy lots of pre-cuts. No, they are
not pre-shrunk and they are not always accurate. If you buy pre-cuts,
be prepared to work around this. I starch all my fabric heavily including
pre-cuts. They do need gentle handling though. To avoid lots of stretching
I cut my jelly roll strips in half before starching. Press (up and down) and
don't iron back and forth. Hope this helps.