One factor that could be important here is that one CAD exchange standard doesn't currently do a very good job of modelling wiring harnesses. This problem first

One factor that could be important here is that one CAD exchange standard doesn't currently do a very good job of modelling wiring harnesses. This problem first showed up on the A380 when different CATIA versions were being used at the two Airbus design centres. A solution is being worked on by a joint Boeing and Airbus group but will be a while before it is published.