I was making a booking to YYZ on KL site a few days ago, there was no flight availability by plugging in EDI-YYZ but by using multi city I could get a routing through DTW, but at the end I get a message to call the service centre as online booking was "not possible", so I called got a very pleasant agent, explained the situation and she was able to pull up the same flights as me, but the system wouldn't let her book it as the connection in AMS was too short, my flight from EDI arrived 08:40 and the DTW flight departed at 10:50
How long do they think I need?
So off I went to Expedia and booked the same connection no problem, except now my return with NW is to LGW and then to EDI with BA so lost revenue to KL.