Shed, that's a well reasoned point and certainly the code share and through ticketing opportunities are far greater at the IAH end for pax originating in MAN than the other way around. SAS's evening flight to Oslo could be a code share and whilst a ten hour layover sounds crazy, especially for business travellers, it would be by no means excessive compared to some routings offered between points around the world.
These days company travel finances are stretched. I know of one oil company which has to move people from a US location to a South American city on a regular basis. There is no direct flight between the cities concerned. They can fly their people over a thousand miles in the wrong direction for a connection and have a journey time of twelve hours but the cost is the best part of $500 each way more in economy and almost double that in business than the fare through an airport on a more direct route with a cheaper carrier and a journey time of nineteen hours, eleven hours of which is spent on the ground at the intermediate airport. Even multi billion dollar oil companies are using the cheaper option, especially where the journey is not counted as part of working time.