I thought I read a post from Support where if a lawn is really low on moisture, it will water the next day even if precipitation is forecasted, because the precipitation isn't guaranteed.
Looks like your lawn ended the 23rd with .07 in (14%) moisture. Next day was forecast to evaporate .14 in. So if they didn't water, and the rain didn't pan out, your lawn would have ended the 24th with -.07 in (-14%) moisture.
The Iro gave you some credit for what happened -- the rain + sprinkler jumped the moisture level to 110%. A moisture level that high could give you savings by being enough to add an extra day between then and whenever the next watering is.