different iCloud and iTunes ID, but want to use gift card credit
I have a separte iCloud and iTunes apple ID's and I redeem gift cards on the iTunes store. I want to use the credit I have to upgrade my iCloud storage, but it bills my credit card on file instead of using the credit I have on iTunes. Anyway to override this since it is billed monthly, so next month it takes the credit I have?
MacBook Pro, OS X Yosemite (10.10.3), iphone5s, ipad Air1