Process Credit anyone done it?

I have just been given a gift from friend to get year membership and I did market sell now have positive balance and upgraded for annual membership but the number hasn't adjusted.
I am bit confused because the amount didn't automatically go down.
Yet I read:
Using Your US$ Balance to Pay Premium Upgrade Fees

Any credit on your US$ account balance will automatically be applied to premium upgrade fees.
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But I am confused down lower they say something about the sell of Lindens being seperate thing and I sold enough lindens from a gift from my friend to go yearly.

Sorry if this sounds stupid but does that mean they are just being slow in withdrawal it from my credit and it will withdrawal the premium upgrade first in my us account balance first?

Thanks in advance,
My brain isn't rezzing properly
FD

Well, they usually do the drafting at midnight SL time of the day you upgrade, because that's how they do it for my annual and my tier. Give until then today and start worrying after that.

Thanks Raudf, I wondered about that.