Again, times are pointless in xc. I've seen 24:00 xc guys run 28:00 on sloppy courses. On a bone dry course with short grass or sparse grass the dirty becomes almost like a track surface. With taller grass and/or wet grass your foot will sink a bit and you'll lose friction.
Basically the ground conditions dictate how fast you are able to run. Your muscles produce force, this force is sent downward and then the ground returns force. If the return force is lessened in any way then your speed will be lower. "For every action there is an equal and opposite reaction". A downward and backward force (your legs hitting the ground) is returned as an upwad and forward force (your running stride). The point of contact, the ground, can change the return force dramatically.
If you were to improve 19/second a mile on a bad course you would likely win the damn race. Basically go for placing among your team/race. Improve your position and the time will be whatever.
Alan