Electric costs?

I have a 3.5 card rig ( Two 2070 Supers, One 2060 OC Edition, and a Quadro p2200). All mining raven coin. The mother board is an old dell board from an XPS 8700 I5 4460 CPU.

T-Rex is saying 600 watts @ 80mh & I figure the PSU ( 1000 watt & 750 watt 80 Gold) & CPU at another 150-200 watts (being generous).

That's 800 watts total.

My electric cost is .06 cents per kwh. According to my math my bill should only be about $35 more. Got my bill today and it about $90 more than it should be. My rates are the same, did not change.

I have bought a watt meter but I wanted to know if any of you had any surprises like this over the years?