I chopped a couple of pairs of cinelli bars down, 64s and 66 i think, the long tail at the bottom was all but useless for actually riding on. Unless yours are brand new and unmolested, i'd reckon that's what the score is.
It's also not impossible that cinelli changed the design/mucked things up and had several different lengths during the years they made them. I know i had one set with the central shim about 1cm off centre, and a mate had a set where the left and right bends were at different angles :shock: so a longer/shorter tail wouldn't really be a surprise (different length tails on the same bar would be interesting!)