Dwayne, I think the confusion is coming from his statement, "our deal is for $50.00 onboard credit each for up to two people in the same cabin". That does not mean they each get a $50.00 credit for one $100.00 deposit. There is only one $50.00 credit for each $100.00 deposit. They each made a $100.00 deposit so they each get a $50.00 credit.
His statement "seems that if only one of us purchased the program last year and stayed in the same stateroom, each of us would get $50.00 anyway" is incorrect.
It is one $50.00 credit for each $100.00 deposit.