Well, the idea is, you would want the double notes at the end so that it stays in sync with other tracks of the same length. i.e. a 16 step track in pingpong stays locked to a 16 step track playing forwards. If it worked your way, it would effectively be playing 16 steps over 15 (assuming you have it playing with forward-running 16 step tracks), which definitely could by nice, but is a little harder to intuitively deal with.
As to the timing of the doubled note being off, that sounds like a problem, but my Nemo is in transit so I can’t confirm that this is the case on mine yet.