Onboard credit - per cabin or per passenger?

[schlogee]

We have $400 onboard credit, but when I tried to book a Bungalow at Princess Cay ($229) it says I owe $29 to be paid by credit card since I have $200 and my husband has $200.  Since the bungalows are shared by up to 4 people, why wouldn't they just share the cost across the total credit available in the cabin?  Separate but related - if it is in fact by passenger not by cabin, can I transfer some of my credit to a passenger in another cabin - or do I just have to buy stuff for them?  We got the Princess plus package so this is the first time we don't need our credit for gratuities or drinks, and we like non-ship excursions, so trying to figure out the best use of this credit!

[voljeep]

Call your TA or Princess - they can fix this to use both OBC and nothing else on credit card