Yes the 85 Duro track works just fine in the deep powder and in my mind is better all around. You will find it does dig slightly more than the 80 but when it finds something hard your not getting stuck. But i want to say I have both tracks and I would be happy either way they are both really good.
Having a different durometer rubber doesnt instantly make it unusable. It just changes the optimum conditions in which the track works best! A +1 for hcr10