Owned and 2013 Gen 1 2013 about 18 months ago and I'm not exactly sure why but my son just bought a Gen 2 2015 and it seems as though the seat height is shorter than the 2013? Is this possible or maybe could the bike have been lowered somehow? I'm 6'4 and don't want the bike to be any shorter than it already is. So my next question is can they also be raised higher? Thanks..