Is that more clear?
I always got it. Calibration/tweaking can be done in software or externally via hardware adjustments. Depends on the application and users requirements. If it's for one's own project then software is cheaper as one has the freedom of recompiling the sketch at any time when external things are changed. If however the project is designed to support changes in sensors or other external changes by users of the project then external calibration might be more desired. At the refinery I worked at we used thousands of sensors wired into central control systems, and we always required that any sensors used had the means to calibrate them externally so that we did not have to have 'custom' loop calibrations for every sensor wired to the central systems.
Different strokes for different folks, there is no single "best method", just what works best for you.
When I first read this thread, I wondered if I had the means to calibrate a 0 - 37 kPa transducer. It turns out my smaller Chandler deadweight tester will actually go down that low. I wouldn't be able to match the exact full scale, but 1 psi increments would probably give a good enough calibration.