Man, if I was getting 13,000 miles out of a tire, I'd never even consider switching. I don't think you could do better than that unless you put a car tire on your bike. I've never used a Battlax tire, but I've gone through a good many Bridgestone Battlewings, and I don't think I ever got more than 6000 miles out of the rear. I eventually switched to Shinko 705's, which tend to get even less mileage than the Battlewing, but they're a lot cheaper and easy to change by hand.
I'm planning a long trip this summer, and I'm probably going to switch to either a Heindenau K60 or a Mitas E07 Dakar, both of which seem to get a lot better mileage than anything I've been using.
"No matter where you go, there you are."