Bobrun,
I haven't checked but I will trust your figures;-)
Another important consideration. If you join as a DEFO you have a basing and you have the CHOICE to move to HKG in 4 years. If you join as a SO, you will upgrade on the aircraft they tell you that you are upgrading on and then you can 'bid' for a base. As my other posts outline, I think basings will become very hard to get.
So join as a DEFO and you can still choose where you want to live - join as an SO and you are pretty much committed to HKG.
The education allowance will cover up to 2/3rds(after tax) of your school fees so that means you will be out of pocket $20-30K per year.
The housing allowance isn't the financial panacea that people make out. Lets say it is $50K - you pay tax of around $8K, management and government fees(you don't pay if you rent) of another $5K which gives you about $37K per month to go off a mortgage. If you buy a 1,000 sq ft place for say $5-7million, your interest component will be $20-30K per month if you borrowed 100%(usually only able to borrow 70-90%). That means that you are paying off your place at the rate of $7-17K per month. That equates to about GBP5-12K per year or $12-28K AUD per year. So you are relying on the property going up.
So on the balance of all that I still have no problem recommending FO over SO!