Why are they so long? That's 6" longer than your DL......They could be much, much shorter. Given that, you are borderline 500 and 400. Best to be overspined than under, stick w/ the 400's, or cut them down and use 500. You aren't hurting anything w/ them that long, just not necessary.

Yes, by cutting your arrows down by 5 or 6 inches, you'll lose about 40 grains of arrow weight and increase your speed by...oh......6 or 7 fps. They just don't need to be that long. Unless you plan on growing really fast and increasing your DL....