Measurement of wall moisture: How can the result be assessed?

After a change in the rainwater drainage at the house

but now it is unclear whether the walls still have a moisture problem

Is there even a moisture problem at all?

So far we still don't know what kind of moisture problem you had in the house? Did rainwater get inside? Flooding three years ago? Have you bought a hygrometer to measure the air or a moisture meter to measure the walls? It somehow reads like the former ;)

That's only a difference of 11.4 measurement levels. According to the device manual, Dry is 0-24, Medium 25-50 and Wet 51-100.

If the manual gives you guidelines, you don't necessarily need expert knowledge yourself, but you should be able to assess the overall situation on site. Moisture cannot be measured alone. A forum cannot tell you from a distance whether your walls still have residual moisture. Other factors also need to be considered besides the measurements.