I've no idea of your street layout, but I wonder how much location of the DP is making to those estimates.
You will likely have many scenarios where someone has a DP at the end of their drive so only need a few final meters of copper, whilst someone on the same cab, but furthest from the DP may need say 50m.
It all depends upon the layout of the cable, in just the same way as with how on FTTC you have some people very close to the exchange, yet the line distance to the cab is more than double. Just because you may be nearest to the cab, doesn't mean you have the shortest line length than someone who may live further away, but nearer to the UG joint box.