Yeah, it's an authorized Ducati dealer. As for why I spent the $500ish, it's to "correct what wasn't done during the 600 mile service."
In other words, let's just say that the local Ducati dealership isn't the most desirable place to get service done, and the local Ducati mechanic (who is known for doing good, honest and knowledgable work) is a better option (both service-wise and financially). Since I went there for the 600 mile service and didn't go to the Ducati dealer, it was the $75 here, $75 there, $150 here, $133 there to "fix" the work of the aforementioned Ducati mechanic.
So, whereas this work should be covered under warranty, I had to pay to get it fixed. No big deal, as I was willing to get it running correctly (since the Ducati mechanic was Mathesis-free). But, since it's one thing after another, it's now setup as-per-Ducati's specifications, and it's been warranty work since then.
The best thing is that they told me that "checking the antifreeze level was something that's done at the 600 mile service" and even though they have had the fairings off four (4) times, the Ducati dealer failed to notice it. Also, they've tried to feed me the "it's been low since the 600 mile service, and that's why I have the problem now." My retort was that it's a sealed system, and the only way for air to get in is to have a leak. Touche'.
So, the service manager is getting with the local Ducati rep to see if 200+ is the normal operating temperature for a 749 and if 220-239 is within reasonable specs for stop-and-go-traffic

. If not, that's when they'll test the sender and thermostat. Under warranty, of course.