Check out the screen shots in this post. It shows a framing square and gives a visual of the difference from cut and engrave at the moment and what is possible.
Know that you can address the 19.5 size for cutting even if you have an engraving in GFUI. As long as the engraving itself lies within the go zone of the bed. So you can cut out a bigger area than you can engrave all in the same operation. One way to insure that you are getting everything is to make sure all the objects get the color highlight when you click on them in the GFUI after you do the settings. If they don’t light up, they are no going to be processed.