Flatten route with splices

Solidworks seems to keep pushing how great splices are now in the electrical package using 2020; however, I am finding nothing but frustration when it comes to flattening a 3d manufacture and annotation route containing splices. I have tried multiple scenarios using a test harness I created (see attached power point); everyone leading to the same result: garbage. I am being told at this point I have to model a separate harness assy to be able to use in the drawing and manually drive the wire lengths reported from the "real" harness routing. Any suggestions?

SolidworksRouting