I'm embarrassed to say that after 1500 miles, I think I've discovered a feature of my 10 year old Campy Mirage shifters. Seems I can adjust the trim on the rear derailleurs with the inside lever that downshifts (upshifts? Not sure of the convention). I can partially depress that lever to move the derailleur just a little in the direction of the smallest cog. All along, I thought the shifters only moved the rear derailleurs up or down a minimum of one gear.

Do all shifters work this way?