Don't know if this is helpful or not but i remeber awhile ago i was using the POI to see the closest petrol station and when i clicked the closest (2km) it routed me to it but cause of the way the roads were it said it was 3km away.

Im just wondering if D3 just calculates the GPS address from current position to the position of the poi to get the amount of km it is from your current position.

It was ages ago when i noticed this in the city so i could be wrong but im just curious is this could be a way to give us a rough distance calculation for poi?