Your profile would suggest that you are past the beginner stage and you state that you are an engineer. Since no camera body or lens comes off the assembly line exactly the same, although made in the same factory and using the same specs, such a test as you would like to see is not practical even in controlled conditions by one person but especially when being done by different people in different locations, imo. It appears nothing is wrong with your gear but that doesn't satisfy you. You state that you are scared to tweak the menu yet all you have to do is do a camera reset or do as all competent engineers do - take notes on each phase that you go through, compare results, make changes as necessary and if you aren't satisfied, start over. The learning process doesn't cost anything but time and effort.
Nobody should seek his own good, but the good of others. <><