Exactly. Even with the same model, a calibration done with the same equipment by the same person. the settings will vary. They will look similar but one display may drive red or blue higher then the other. So when you adjust it it will have an impact on the low or high end so it changes everything.
Then when you look at certain models like Sony where you don't have a CMS your primaries and secondaries are where they are. So even the same model between two different displays will track them at different points.
I guess for me thats where I have this view on people just throwing the word calibrated around when they just used other users posted settings.
There are so many methods and techniques. Last one I did I did 5 different methods checking native color spaces, rec709, blue green led profiles, etc. used different meters, chromapure, calman 5 ent, lightspace, various pattern sizes, apl non apl windows, patterns from videoforge, lightspace, etc. to maximize the picture and fix various things I found.
Not to say I haven't shared my settings but I let them know each time this doesn't replace a real calibration.
