Full price for ultimate code

Hi and thanks for reaching Microsoft Xbox gamer's community. My name is Josef.
I'm an Independent Advisor and a Microsoft Xbox user like you.

Hope you're doing great today MC.

Nope, you shouldn't be charged for redeem a code.
Just keep in mind that the code doesn't need to be a trial or similar.
Probably that happened to you previously (or maybe you let the subscription renews)

But as a personal recommendation, always use the Microsoft store or authorized retailers if you want to subscribe or purchase a redeemable code for Xbox game pass ultimate

It's because you're trying to add it to a Game Pass Ultimate subscription. You would need to cancel that subscription or wait for it to end before adding the Gold code in order to get the full 12 months of Gold. Otherwise, it will be converted. The codes
are converted based on price rather than time. 12 months of gold is equal in price to 4 months of Ultimate.

If you add a prepaid gold or game pass while you have an active Ultimate subscription, it will be converted to Ultimate since Ultimate includes gold and game pass (it does warn you before you complete the transaction). The codes are converted based on
price rather than time. 12 months of Gold is equal to the price of 4 months of Ultimate. In order to use just the full 12 months of Gold, you have to add the code after your Ultimate subscription ends or you cancel it and it has ended.

When you already have Ultimate and you add a standard Gold or Game Pass code, it will convert the code to Ultimate at a ratio based on price rather than time. 12 months of Gold is equal to 4 months of Ultimate. If you want to use the full 12 months of just the Gold, you would need to cancel your Ultimate or wait for it to run out before adding a new code.

No as its only a one time offer

You can buy a ultimate subscription again but you will.have to pay full price

Or.add months to the ultimate pass at full price sincr its only month to month