Customer has this cutter, and when selecting the size 10 stone and it cuts, the stone circle is a little too small- I am not personally familiar with what the advanced step size setting would be that he would want to enter, as the only option in the step size edit for that cutter in the program is “manual entry- how to change?

Under the plotter options will be an Advanced option.  Enter the 10 x 10 size if you cut a 10" x 10" square.  Then enter what gets measured on the vinyl. Say 9.75 " x 9.75 ", for example. Click Calculate Scale.  Then the new resolution would look like this...





Note that the resolution, in my example has changed from the default 1016 to 1042.
 

If you suspect that the plotter resolution in the driver does not match the plotter resolution for the device, then it is best to cut a 10" x 10" square, and measure it accurately on the vinyl.  Any discrepancy of measurement can be accommodated for by the software.