How OTM calculating Loaded Distance, using PcMiler?

Hi,

I have a doubt from where the loaded distance is getting calculated for a shipment. we are using PC miler and Sometimes shipment loaded distance and PC miler distance does not match in OTM.
For Example: I have one Source and Destination Location. Using PC miler i did Rate Distance Enquiry and it showing the miles as 245.8 for this Source and Dest. I built an shipment for an order having the above source and dest location, at that time the shipment showing 200 miles in Loaded Distance field and in Shipment stops tab.

I want to know how PC miler miles are integrated to the Shipment Stops field and Loaded Distance field. Is there any java class function used for fetching the values from PC miler to Shipment fields.