Balancing ideas and delivery

I got a riddle for y'all today....hehe...more airik mind games....

Short in Change
1) Three guyz want to order delivery, so they call the pizza delivery to send them a pizza.
2) When the delivery guy arrives, he askes them for $15. So they split the $15 up and pay $5 each
3) When the delivery guy gets back to the store, the pizza manager tells him that the pizza only cost $10. He tells him to go back and give the customers the $5 back
4) On the way back to the customers, the delivery guy thinks to himself. There are 3 of them splitting for the pizza, they wouldn't be able to split up $5. I'll just pocket $2, and I'll give them $3 back so that they can have $1 each.
5) The delivery guy arrives at the 3 guyz door, and gives them back $1 each
6) If every guy originally paid $5, and got $1 dollar back, they each paid $4 for the pizza.
7) $4 * 3 guyz = $12 ; if the delivery guy also only pocketed $2, that would make $12 + $2 = $14.

Huh? Not $15??! Wheres the missing dollar?!?!

aaaairik.