Now if you have a C# development environment, XYLenTech who wrote ThreeDubber posted the source, so you're free to fix that and recompile. You'll just have to make your slicer write the amount of filament used to the gcode, then translate the line to match what the XYZ machine wants.

I did this for slic3r and Cura in my custom port of ThreeDubber.

I suspect though that the machine also might use the layer count to help make the estimate more accurate. With just total_filament set, I get some crazy estimates sometimes, but eventually it evens out a bit. I havent had time yet to figure out how to get slic3r to report the layer count so I can translate that value.

I think total_filament was set to 1 not just for convenience, but in an attempt to keep the machine from counting down the filament spool. I think tests have shown though that that doesn't work, so now it's just an annoyance.