iPod Nano and Bose QuietComfort 2 headphones

I purchased Bose QuietComfort 2 haedphones today; very impressive with my Nano. The headphones have a hi and low setting; battery operated devices like the Nano should use the high setting, but I found only one earpies worked on hi and it was distorted. The volume is limited at the low setting. Anyone else noticed this? I'm hoping the battery charge time for the nano is not reduced by using the low setting on the headphones. Any comments or experiences to share? These still sound the best of the noise cancelling headphones I have tried.
Thanks

ipod nano Windows XP Pro