these days a customer asked me about some strange behaviour within a simple tour planning call: though he requested ROAD based computation of driving time and distance the engine obviously returned geometric values.
This effect is caused by a configuration parameter (dima ini-file) that is called SectionBuffer. The default value is 20000 (meters). This buffer defines an area around the given coordinates: streets outside this area will not be considered. If the routing isn't possible within this area the server processes a fallback to geometric.
Well, why does this happen in the given case? Simply because the destination (red flag) is somehow isolated
If this occurs in your environment you should check whether disabling the section buffering (SectionBuffer-1) prevents you from this effect. It helped me in the given example.
Regards from Germany,
Bernd Welter