I see the error, M92 doesn’t allow multiple extruder configuration like Marlin.
So how does V2 help? What module are you referring to?
Since STACKER uses Repetier, I would think that they would have noticed this problem. No doubt if they used three different colors, there would have been a noticeable dimensional difference between their parts being printed at the same time.
I’m printing a part that has a tight tolerances for a bolt, and then the sleeve must fit into a socket. So the exterior dimension and the interior dimension for the bolt are highly affected by any sort of under or over extrusion. Multiply that by 3 different extruders, and all sorts of dimensional inaccuracies are possible.
Rule: A profitable manufacturing process, must be duplicatable, with little to no extra time in post processing. When a time component is introduced, manufacturing costs go up and feasibility of the manufacturing process goes down.
At this point and crossroads, I’m afraid that Ditto Printing has its limitations, unless individual controls to the Extrusion Multiplier, or Esteps can be adjusted. The only fix to this, is to use the same exact filament color and batch per printer for all extruders.