Maybe the LBS guy was talking about the fit of the cup into the frame, not the bearing adjustment.

If your wear is just where a few bearings sit, that's too loose. If it were too tight, you might see damage all around the circumference, but I'm just guessing since I've never seen that in a headset. If a headset were too tight, I think the handling would be objectionable.

Your plan to readjust is a good one. Better to be just a tad on the tight side to properly load the bearing.

Is this a road/commuter bike? Lots of miles on it?