3eng, sorry if you feel a little miffed.
However, vasco has it 100% when he refers to a 'tail wagging the dog' situation.
Amending an RB location by the indirect method of working backwards from an amended start-to-AP distance (or time) seems bizarre - is the AP then recalculated for the changed time in contact for a larger RB, if it is moved to an earlier point. With the A310 system, you simply drag the start point (or end point if that's the preference) and the system recomputes the RBs and associated APs.