I think a 13T pinion on that motor with a 25A ESC is probably pushing it a bit. I bet that ESC would run much cooler with an 11T, but of course, your headspeed will be lower...

Still, 10mins is a pretty good flight time. It sounds like you're flying until the battery is depleted to the point that the ESC starts reducing power. That's way too far! You never want to discharge your LIPO more than about 80% if you want to get the maximun lifespan out of it...