My response was meant more for your second question but yes, I suppose, if I know the watering, fertilizing and mowing history I may not get the soil probe out of the truck. Obviously, I am not going to suggest a fungicide if any of those things is wrong.
In my opinion, fungicides entail a level of care most places I work would not consider. Typically by the time they call me things have been ignored far too long. I have had a couple coaches insist on sprayimg fungicides right away but once I explained the changing weather forecast and planned nitrogen app would likely take care of it they were happy to not spend more money. I have probably sprayed more fungicides and more types than 95% of the people here but my last golf course job was almost 30 years ago and there have only been a few dozen apps since then. To me it's like step 99. Guys hit with pythium or real bad brown patch would have to spray but I do not see much of that any more. When I see symptoms or signs of those, or dollar spot I don't think examining soil moisture is step one or absolutely necessary. What is important is making an accurate diagnosis before acting.
Like Bob Dylan said, "you don't need a weatherman to know which way the wind is blowing."