Every price on this page is a “from”. That is not a hedge — the same code covers a filter you clean by hand and an assembly that costs three hundred dollars, and there is no honest way to know which is yours from a phone call. The diagnostic settles it, the scope and figure are written down, and nothing is opened until you have agreed to them.
The fee is credited toward the work when you go ahead. On a job we carry out, it is not an extra line on the bill.