Hi, you have your stats and that is ok.... im not telling that you are wrong either because i really have no idea on how this work... but here comes my theory!
May be is not abut you entering late or earlier.. may be is on your mind. Let me explain:
If you are one of the first entrans... may be you feel relaxed, calm because there is no hurry to finish it, so yo play wise, slow... and more conentrate.... so you play well
if you are one of the middle entrans... 30-40.. you can become a little obseced to score well because you want the credits soon to buy balls, oar equipement or simply enter another ready to go. But you are not in a hurry either; but not as calm as if you were one of the first entratns... that is why yo stil get a decent one.
In you are one of the last you are in a hurry, so you play desperately and you can play with less brain and more intuition or feel....
dont get mad please, just a different poiny of view for not to invalidate your point :)