I have 2500 miles on Mirage QS 10 Sp shifters and compact FD. Have to press the thumb lever twice to get the FD to move chain to small CR. First push just trims the FD but I can't push it any further until I push again. In contrast, on my 2001 Chorus levers, I can go all the way through the clicks with one push and the FD moves to the low position. Why doesn't the Mirage work the same way?