Part of the problem may be the indexing of the STI shifter. With friction shift (the only way to go on the front derailleur control, as Campy still realizes), one can control the motion of the cage and guide the chain to avoid overshifting. Also, being able to fine-tune the position of the front cage allows a narrower cage to be used, which also reduces the chance of overshifting.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069