Hopefully this is a simple question. Lol. Seems when I hatch 8 to 12 eggs they all hatch maybe except for one. Put in 22 and only 14 hatched. Because there more eggs should I up the humidity at lockdown more so when they r only 8 or 10 eggs?
I'm guessing that your issue may be temp variation in the bator. If you're using a hygrometer, 30% during days 1 - 18 should not matter if it's 8 or 20 eggs. Same for lock down at 65 - 75%. But, if you have warm/cold spots, I'm guessing the cold spots are in the corners, which could be why your full bator hatch % is down. Not knowing your set up, or any other variables, I'm only guessing based on my mental picture of my set up.
Usually there is a better hatch rate with more eggs due to stability. The more mass in the incubator the more stable the temperature will be. Humidity readings are the readings and number of eggs would only change the surface area of water needed for certain RH due to more eggs evaporating moisture. The reading is the reading, if salt test calibrated then it's a true reading, only the amount (surface area) of water will change for desired RH.
I agree with Lazy Gardner that we need more info on your set up and circumstances during each incubation attempt. Forced air or still air, changed thermometers or where the eggs were obtained from...etc.
anything over 40% may be a bit high for the first stage. I would shoot for humidity more in the 30% range, personally. Humidity above 65% for hatch is ideal, whether there are 8 or 80 eggs in there. It shouldn't really make a difference, except that the more eggs there are in there, they may slightly raise the humidity as they hatch and release liquid into the incubator.