I’ve found that when using my soil PH probe that my Ph will be different at various depths and that how much moisture is in the soil will affect the reading.
I don’t check it right after I water but wait a day or two so the soil dries a bit. When it’s too wet like just being watered or when it’s too dry like just before watering the readings aren’t going to be accurate. When moisture reading is between 4 and 8 on my meter that is the sweet spot.
So when inserting 3” it is around 6.8
At 6” around 6.5
At 9” around 6.2 and all those are fine for me as that is between 6 and 7 and different root zones of soil will provide one thing and another zone another.
Just sharing my experience using soil probes over the last year running all organic grow. I don’t water to run off nor adjust my Ph of my RO water nor teas etc. the critters and the plant roots will adjust things as needed.
Not sure what soil meter you are using but I have 3 different ones and this one is my go to and is spot on and I have 2 of them just in case I wanna verify things.
Here is a link to a write up I did about a year ago explaining as I understood things back then as to how they work etc.
Always learning more as I go and thinking changes but for the most part this is still accurate for me.