That seems about right. DASH has become like gold, hard to mine. The best calculator to use daily is whattomine.com I find it is closer to what you would get that day. When I started mining DASH in August 17th 2017, I got 0.45 on 11GH exactly a month after its gone down to 0.18. I expect it to get harder with the deliveries on more D3, DM22 DR-100. The Law of Diminishing Returns.