I'm looking for a dropper seatpost--a Specialized Command Post Blacklite in particular. I want to get the 30.9mm x 125mm (drop) size, which comes in two overall lengths: 380mm and 405mm. I know the 380 would fit since the seatpost that I have is a 380mm. Before I bid on one of the longer ones I'd like to confirm that there is another 25mm available in the seatpost? My current seatpost sits about 7.5" "out" of the seat tube.