[Steve Tinker]

And to add to the confusion, it depends on who uses anti-seize compound to the plug threads.
I believe that also "changes" the torque required to seat new or old plugs correctly.

I personally use anti-seize but there are a lot of people who just screw them strait in the head without any lubrication. That's great when installing the new plugs, but can become really difficult to remove when they have been in situ for 50,000 miles with a million heat cycles and no lube .....