"He who marches out of step hears another drum." ~ Ken Kesey
I think I understand what you're describing. Sounds like interlocking. I'm not a fan/believer of that myself, but to each his own.Sounds like the printer is wanting to print black down first with halftones and the halftones to knock our of the middle grey and the top white.It sounds like this should be more of a raster (pixel art) file rather than vector. You could take the black file, bring it into photoshop and make the halftones from that vector file by converting the image mode to BITMAP, keep resolution high like 600ppi. Bitmap to the LPI needed (55lpi, 22.5 degree screen angle, elipse dot shape. Then change the mode back to greyscale. Now, you then make your grey screens however you need to, then make selection of the black (each and every pixel) by holding down the Ctrl/command key and clicking on the black channel. Then move to the other WHITE and GREY screens and knock out of those.What is a bit confusing is the mention that "The printer already has the black". Whats that mean really?