Don't you think that 18% jump might just be from something else going on around 6th at the same time, like a new spot opening nearby or a street fair? Two months of data is pretty thin to pin it all on some reviews that half the people didn't even mean to leave.

Been there with a tool that cried wolf on every single scan, total waste of money and time.

Had a buddy run into this exact thing on a shop slab last spring, ground looked dry on top but had been soaked a week before and the meter said 22%. He ended up with a soft crust and hairline cracks all over one corner, had to grind it and patch it which cost him a weekend and some cash. A quick check with a meter takes two minutes and can save you a whole lot of grief.