you will have to run your own tests
if its cut only accuracy then tell the plotter to cut a 1000mm box then measure it, normally in the plotter menu is a compensation value you can enter in percentage. but that will only work on that particular vinyl. probably different if you laminate it.
the scan width should always be correct
if its to match a print has the printer printed the correct length to start with.
don’t know your system but the roland is self compensating my graphtecs report the scanned printed distance and allow me to alter before sending the cut data.