So it isn't worth spending $400 on card that has same speed as $200 card.
38% wasn't from me. I was using similar method of extrapolation. I get 160S on 480, no overclocks. ~60% MCU on Claymore 6.0.
Bether bang for the buck on the cheap 1060 3gb and private kernels. The public Zcash sp-mod #1 produce 80Sol/s on 60% tdp.