Darkness and Metal - more than +10 damage?

[Android17a]

On darkness energy, it says the damage does an extra 10 if it has dark energy attached. If I was to attach, say, four darkness energy to my Dark pokemon, would it then do an extra 40 damage for its attacks, or still just an extra 10?

And I ask the same thing about metal energy's -10 damage rule, would that also double up?

[dkates]

Yep! In Unlimited, that's a big part of the Sneasel "strategy". Same with Metal -- it's a big part of Steelix and Scizor strategies.

[Android17a]

I wondered, because an Agron (R/S) with three metals is one of my killer Pokemon right now.