Running down the highway temp rides right at 180 or just a touch lower which seems normal/good as my t-stat is a 180 unit.

As far as the lock up of the fan at idle I have my doubts on the Jag based clutch as it lists as standard duty. From reading I found this on allpar

"There are light-duty and heavy-duty fan clutches, and within those categories they differ in such things as temperature setpoint and presence or absence of an idle-lock feature.

The idle-lock feature, usually found only in heavy-duty clutches, drives the fan whenever the engine is at idle or low speed. Without the idle-lock feature, the clutch is purely thermostatic. If the air coming off the radiator isn’t hot enough to make the clutch engage, the fan will not be driven. In situations calling for assured airflow at idle and low speed (such as a car with air conditioning, or low-speed/stuck-in-traffic driving), the idle-lock feature is good to have."