The data on the soil moisture graph and the value in the sensor view do not correspond. Why?
The graph shows how much water is in the soil, while the value in the sensor view represents the percentage of water available for your specific plant. Thus, while the graph is not plant specific, the value showed for the soil moisture is linked to the model of the plant. Let's assume that you have a plant that likes a very wet soil: it can be that the graph will show "moist" and the percentage will be around 0, as that specific plant will need to be watered again, once the "moist" level is reached.