@aeromitch37, welcome to the community! We're thrilled to hear you're loving your Iro.
Good question. You are correct in your understanding of the moisture balance equation.
Just curious, did you happen change any of your zone attributes after the Flex schedule that ran on 10/5? I'm curious if the soil reservoir inputs might have been adjusted? These settings include root zone depth, soil type and/or allowed depletion. In reviewing your zone settings, it appears you might have changed your root zone depths for warm season grass from 9" to 6"...
Current soil moisture level -- note the irrigation total on 10/5 (.54 in):
Forecasted soil moisture level -- note the irrigation total on 10/12 (.21 in):
Could you please confirm any changes made to your zones and I can better explain the discrepancies you're seeing.