Probably only makes sense to make a personal tax deduction (i.e. after income tax) contribution up to $3,000 as a 'partner contribution' to the wife's account. I.e. 3000 / 100 *18 = 540. The husband is able to claim this rebate/offset in his tax return.
The further $7,000 is probably better as a salary sacrifice (i.e. before income tax) contribution, as the husband has an effective tax rate of 30%. By pushing the $7,000 into super this way, it is taxed at 15% on entry (i.e contributes $7,000 - (7000/100*15) = $5,950 into the super.
If done post tax, the same $7,000 is first subject to income tax of 30%. Which really means (7000 - (7000/100*30) = $4,900 into super. Does this make any sense?
Watch out of the contribution caps of $25,000 for this financial year on salary sacrifice and Super Guarantee contributions, because if you exceed it you pay tax at the highest rate on amounts in excess of the caps.
In short, the 'partner contribution' doesn't reduce your taxable income, it provides you with a tax rebate/offset (not sure of the right word to use). Max has in fact, not reduced his taxable income by $10,000 in your example.
This is not financial advice, and you should make sure you check out any information you get on the internet!!