<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Spider:
Also, I have a forced stopover on my return leg. Could this somehow affect the total mileage?</font>
Probably. SYD-LON is 10555 miles on a single-number flight. But if you fly via LAX with a change in flight numbers, then you're doing 12951 miles. So it all depends on the routing.