I have the same/similar problems
You can partially bypass the problem by manually setting the % moisture for each zone.
I have 8 zones, and it is a bit of a pain, but it aleast it temporarily reduces over watering.
I think their equations for calculating evaporation are incorrect.. it always says the soil is dryer than it actually is..
and then it starts to over water like crazy.
The worst part is.. when you call the company – they don’t seem to understand that over watering is a problem.
The *reason* i bought this was to reduce my watering.. but this stupid thing over waters like crazy.