I am creating an instance of mappoint, loading 2 datasets totalling about 50 locations.
I then index through the locations and calculate the driving time between each location and every other location.

When I assembly a route in another instance of Mappoint, the total drive time is often longer than the sum of the segments.
In a 20 hour drivetime route with 12 stops, the total route is often 3 hours longer than the sum of the segments.

I have to increase the driving speeds to almost maximum on the assembled route to get the same time as the segments.

I am talking about drivetime not triptime.

Any idea what could be causing this??