Upon reflection, they might have worded it that way so that the CC deduction happens against the highest earner's income. As it stands, the CC/benefits usually go to the lowest earner. So if your partner was earning, say $65K, and you were about to start work on a part time basis to earn $30K, as a couple you would want the CC fees to be deducted from the $65K person's tax, not the $30K person's tax. Or something.