I own a H9 Max and a H9 Core. I want to upgrade the H9 Core with the free algorithm before the March 31 cutoff date if for an unknown reason I want to sell the H9 Max and keep the H9 Core in the future. When I go into the ios control app store I am unable to buy or use the coupon for the free algorithm on the H9 Core because it says I already purchased all the algorithms. What is the correct procedure for using the coupon to apply it to the H9 Core in this situation?
My guess would be to unregister the H9 Max, then use the coupon on the H9 Core, and then re-register the H9 Max again. Is there an easier or better way to accomplish this?