Should i be trusting runoff ph?

so for the past 3-4 weeks i have been having headache with the runoff testings . maybe i torture my self too much but i like to explain everything i see. and what i see is that in soil the runoff ph is crazy . i have 3 ph meters and 2 soil ph testers . dont ask why. the thing is that the runoff ph could be 8.0 or 7.5 or 7.2 . but the plant looks fine plus when i test after the watering with the soil testers (long ones to the root) the ph is like 6.7 or 6.8 . then i also take some soil from deep and i do the soil test where i soak it to RO water for an hour and then test it . that gives me also resonable results. so should i stop testing the runoff ph as it comes from the bottom of the pot? can someone please explain to me what the reasons for that is? is it happening to others as well?

thanks