As marki mentioned; I always use the 5x rule now also. I have a library of 25-1x1, 25-2x2 darks,bias. nom,nom.
Best thing with TEC regulation is you can run a dark library
Leave it on for the whole day and take darks each of binned and 1x1 mode.
Reason I asked earlier was that the data seemed too noisy in that stack.
Just be careful if using the new MaxDL with new QHY drivers; the temp has to be the same for exposures and calibration frames, otherwise MaxDL gets upset.