The most obvious aspect of the two attachments is that the integrated route is quicker !!! - even with the additional 1 second wait time !!
Here's a proposed reason:
For a direct route from warehouse Milwaukee to Minneapolis the client is choosing the route through city-grain-cattle-leather-wires....
wh_direct_route_timing - warehouse round-trip travel time 2:57
But for an integrated route where I insert a stop at tools, the client necessarily has to choose city-coal-tools-pipes-wires on the return journey...
wh_integrated_route - warehouse round-trip travel time 2:55 (2 seconds less)
So one explanation could be that the track route city-coal-tools-pipes-wires is shorter than city-grain-cattle-leather-wires.
If so, why didn't the client choose city-coal-tools-pipes-wires for the direct route to the warehouse?