Yes, since TM 8.0 a pretty flexible GIS integration framework is used to get distances from external systems. So imagine you want to use real street distances for planning your tours including scheduling, and a different distance for charge calculation based on your contracts. A huge problem before TM 8.0, now pretty easy to handle (including standard buffering, housekeeping, and stuff like that) . Check the GIS Integration White Paper for more details (attached to note https://service.sap.com/sap/support/notes/1685381).
