What I believe would be a simple way to do what you want just using Easel.
Material size example 12 X 8 inches.
Select cut on line, 13 X 19 inches.
position the cut line on the material edge.
Set depth of cut.
Select all, copy & paste
Position rectangel 2 so that the toolpath is overlapping the first rectangle by an appropriate amount.
Rinse and repeat until you have covered the work with tool paths that suit.
Place a rectangle pocket cut with zero cut depth over the tool paths that are outside the work piece.
You should be able to select the direction of cut by choosing which tool paths you run.
You could make the original flattening file the full size of your machine, then just adjust any zero depth rectangles to suit the current work piece.
Safe the file & use whenever you want a board flattened.