I guess that is probably a question to put to Zozz and other folks here.
My rough question to your question would be “NO” but I am not savvy enough to answer that! I know, however, that testers do use other types of instruments for more accurate data.
See maukka, djozz, HKJ, Texas_Ace, Lexel, Led4Power, Zozz, and many others. Specific instruments for specific “accurate” measurements!
Please mind that cellphones don’t always show what the eyes see! I struggle a lot to catch the tints my eyes see, and sometimes it is even impossible to capture them. To the point I prefere not to use those photos to not bias people.