Sea Raycer package coupon question?

[PookaJean]

With the online MYW package, it comes with a coupon that if you purchase 60 minutes of time you get 30 minutes free.
My question is does it have to be 1 boat?
For example: Can you rent 2 boats for 30 minutes each and actually get it for 45 minutes each?

 

[Disney Lifeguard]

Up to 5 boats...I think...