@Dorian for current date we use maximum of observed and forecasted precipitation to determine the moisture balance, for past dates we use strictly observed. So it could be that the forecast was high, but actual observed recorded was much lower at the end of day. So your graph will change accordingly the next day. For future dates we use forecasted values to determine a next watering.
Currently we rebuild calendar daily at certain times of day (12 and 1 hour before potential schedule start time). So if you just watered, that watering won’t be immediately reflected on the calendar, but moisture graph should reflect the new watering date immediately. We are going to add additional rebuilds upon schedule completions in the near future. Sorry for the confusion.