Another little tip, either label or use a permanent marker to put the size on each hoop in inches, you'll know exactly what you have then.
To get the size of a hoop, use the plastic grid thingy that comes with each one, the squares show the actual embroiderable area, which is what you need to know.
Oh, and having measured the outside of my 7" x 12" (largest that can be used without the upgrade) it's not anywhere near 10.5 x 13.5", so I think you are trying to use the upgrade hoops without having installed the software for them?