There is another 50 Watts you need to add to that figure.
Well I just bought a WattMeter from one of the biggest Electric Companies in Europe, ABB and it is working great. I tested my actual two home PC, the one with 3xGTX 1060 3GB was consuming just as the hashrate of Nicehash told me, at 70% power limit they were consuming 255 watt about 85 watt each and 45 watt the board, a total of only 300 watt in the wall.
My back up PC with only a GTX 1050 ti and the board only 100 watt so 65 watt the card and 35 watt the board.
Benchmark only when Nicehash was running and nothing else, I know the processors I have consume 51 and 65 watt each but as I said only Nicehash and the GPU-s running.
I have refrained myself from buying from the guy offering 45 watt but bought a RX 470 normal 8GB and will see results when the cards comes after 3-4 weeks here (Italian customs, one of the worst in all world together with Brazil).