You have only register your preorder codes, not the gamecode.
You can't register a ARR PC gamecode to your 1.0 account, because the PC version is already regster there from 1.0 and you can't register the same platform on the same account twice.
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So much for a free month, huh. At least a warning would've been nice.
Did the PC digital pre-order codes add any game time if you used one on a 1.0 account? Extra game time is not listed as one of the rewards.