Do you have a strong enough case to argue that to a federal agent? Personnally I would not want to take the chance. The way I see it they could argue that you are selling the carcass and not the live animal, just my opinion. Maybe you have already cleared this with the USDA in which case I apologize. To me it just seems safer to sell it live weight and then there is not a question about the legality. I would be the one who would end up getting the a**hole at the government to come down on me. It could all work out the same anyway. 1200 lbs X .90 = $1080 or 720 lb hanging weight x 1.50/lb = 1080. Just adjust your liveweight price up or down to fit.