Dear Scott,

I was wondering, what if Clefable used Metronome on a Wigglytuff. Would
it just do 10 or would it do 10 plus 10 for each Pokemon on his or her
bench? Please answer me back. Thanks.

Kris

If you Metronome the wave, you treat the conditions of the attack as though you yourself had a Wigglytuff.  Check your own bench for the number you have.  So, both explainations were wrong.

Scott