The Campagnolo tech at a clinic I attended around 1980 brought one of the other attendees up to the front of the room, where a bike with a partly assembled Campy Record headset was in a repair stand, handed him a pair of Campy headset wrenches, and told him to show us how he adjusts headsets. After the guy tightened the adjustable cup and snugged down the top nut, the Campy tech announced, "Congratulations! You just performed a hardness test!"

The clinic was mostly intended to persuade dealers to cut down on their Campy warranty claims, probably (including returns of hubs that had been rebuilt with incorrect spoking and had twisted as a result---as the tech said, "Even Campagnolo can't drill an oval hole"), but the point about the headset is worth considering. In other words, it's not unusual to damage headset races by tightening the top lock nut before the adjustable cup is correct.