Going by the rates on carnival.com it looks like a 1a
Guarantee will cost aprox $XXX.00pp(Tax is already added in that price)
How I got that price....
1) Went to www.carnival.com
& looked up your ship & sail date.(clicked on FIND A CRUISE at the top of the page)
2)Chose the cheapest cabin & pretended to book it, therefore going thru all of the booking steps so that it would give me the price WITH TAX.
When going thru the steps...you are given the Available Cabin numbers so you can see if the cabin is near your cabin or not.
I recommend YOU do the same so you can see for yourself.
What YOU can do is...
Call your agent & tell them that you know for sure that there are cabins available.(although the available cabins may NOT be anywhere near Your cabin.)
Tell the agent to take your son out of your cabin(now making it a triple)
& put him & friend in a cabin of their own.
The agent should be able to do this with No probs what-so-ever.
The extra money that you paid for the quad should be returned to you if it's not into the Penalty Phase or they may have to give it to you as OBC.(On-Board Credit)