To each their own definitely dude.
But we each have variables. Nutrients, water, ph, strain requirements, etc. Just because you have good results running at 6.2 doesn't make that right. It just means you've found a balance for what your variables equate to. Idk how you don't get Ca or K deficiencies running 6.1
Biology dictates what pH levels the nutrients are available to the plants in soil or hydro. Not you or me. The water temps related to DO levels and how easily bacteria can grow. The enviro impacts transpiration, etc. etc. I say this because it all starts with the pH and ends with the previously related factors.
As far as "those numbers" I'm always within the correct vpd range for my state of growth. I run higher temps in veg to save on cooling (85) and lower in flower (75-80) but its irrelevant since my hum matches the temp in the vpd chart. Chillers at 66F and sterile systems. Monosylicic, floraflex, and thats it. No deficiencies, and pearly white roots.
Anywho this is the chart I've always used.