To be perfectly honest I have never seen a CAD program that comes with a CAD/CAM package that's any good.
OK they work but their sole function is to get toolpaths into CAM not make drawing easy.

Your problem is the shape, take the top box you call Low 1, you want it to cut outside the lines on top left and right but not bottom. How does the program know that ?

Low 2 you want it to cut outside the box on left, right and top but not bottom this time.

I think you will have problems with any program expecting it to know these variables unless you draw the toolpaths.

Often my drawing bear no resemblance to the part concerned.

Another trick is it's often quicker to not share entities when doing profiles but draw each profile in full on different layers and then hide the layers as you build the program up. This way you don't get double entities.

First thing is to find a usable, to you, CAD package and then import into the CAM program of your choice.
DXF is your friend.