My rear lasted about 3600, could have made 4k before cords, I don't do burn outs and I can downshift correctly. The Metzler just doesn't hold up well to abuse on hot roads in hot weather on very abrasive roads.
That said, downshifting so sloppy that the rear tire skids sound more like just bad clutch control. Don't just let the clutch, slow your release a little bit, or learn the match rpm to next gear.
Hell, I don't even get traction loss when I ride around doing clutch less downshift's and those are far more jerky than even 1/2 asset clutch wrk.