That's true. Phil, why are you opening it to turn eggs? You can just tilt the incubator to the next flat. Temps do not waver on these unless there is sun shining on it, too much water spilling out, or the lid freqently opened.
I fill the water troughs 2/3 full, then fill with eggs, tip to one surface back from upright, next turn is one surface forward of upright. At the end of a week I refill the water troughs to 2/3 and resume turning. At the end of week 2 I do the same. 3 - 4 days before hatch I set the incubator in the upright position, and the day before hatch I add a piece of blotter cloth for a wick and fill the wells to the top. I don't open until it's too crowded for eggs to hatch when I clear out the population when no one is zipping if I can be quick about it. SC doesn't even open then.