Thanks Linn. Sorry I wasn't clearer -- but yes -- I'd like the system to water as much as necessary, but NOT on the day when the guys show up to mow the lawn. As I also responded above, I selected the other 6 days for watering, set a flexible schedule, and this did the trick.
Now I'm looking at weather stations and trying to decide which to go with. I had chosen the closest (about 3 miles) -- a personal weather station. But I took a closer look at its profile, and see that it was offline and not reporting data for several days over the past couple of weeks. I'd still like to find a weather station pretty close to home, but realize that I need to look more closely at it and verify that it has good uptime and a good track of accurate reporting.
Still lots to learn, but really appreciating this system.