The 1080ti has astronomical hash rates for ZCoin. It doubles a 1070 and for the most part that is the most dense ZCoin mining card since not many people got 1080's.
I would be mining ZCoin for the limited time left before they hardfork away that Lyra2z algo. The algo is very low utilization also so enjoy less heat while on that stock cooler
Yes the issue is that all calculators are off, so the profit is usually 50-55% of what is calculated. Do not have 1080 though so cannot say. What is the Lyra2z hashrate for the 1080 and 1080ti?
I had 2.2Mhash/s on a GTX 1080 and ccminer 2.0 compiled with cuda 6.5 (the 8.0 version gives 1.8-1.9 mh), but the profitability was not very interesting : as you said calculators are off. Maybe there are some private miners on amd side, which would explain there is an important hashrate on this coin whereas this is not the most profitable coin with public miners.