Drum dial giving me readings that make no sense?

I set all my lugs to an even set to start tuning a head. From there I turn every lug the same amount yet one lug is like 15 below the rest? And lugs that read the same pressure sound completely different? I don’t understand it!

And if I do somehow manage to get all the numbers to match (ignoring each lug sounding different) how do I get the head to a discernible note? Do yall just a Hertz measurer or can you really find the percussive note?

Tuning drums makes me want to quit my favorite hobby, it’s so frustrating!! Please help me.