"Do I need to authorize my iPods? No, you do not need to authorize your iPods. Your purchased music needs to be authorized on your computer before you copy it to your iPod. For more information on copying and playing your purchased music on your iPod, check out our..."
Slashdot Mirror
Sorry....but the ipods don't actually count as authorized machines. In your scenario above, you would still have 3 "licenses" left.
t horization/
from: http://www.apple.com/support/itunes/musicstore/au
"Do I need to authorize my iPods?
No, you do not need to authorize your iPods. Your purchased music needs to be authorized on your computer before you copy it to your iPod. For more information on copying and playing your purchased music on your iPod, check out our..."