Age of Consent Variations in Australia. Draconian or Not

Hey all, I know you lot are based in the US, but after a quick look around, I couldn't find any Australian sites to answer my question. Hope you guys do better than I have, this sure confused the hell out of me.

After reading several articles and journals about the differences regarding the age of consent in australia, can i ask question to clear up confusion: In queensland, the age of consent for sexual intercourse is 16, except for instances where the intercourse is of a homosexual nature?
And a 18 year old male an a 16 year old female engaging in sexual intercourse is permissable by law, but not in the instance of a 21 year old male and a 16 year old female? Or does this only apply in the instance of carnal, rather than sexual, knowelege?

This variation seems slightly confusing, almost draconian.

Could someone clarify this, and defog my confusion?

You can find the age of consent laws for Australia Here:

http://www.avert.org/age-of-consent.htm

We do not certify the accuracy of the information. The age differences reflect the legal maturity levels associated with those ages. A 21 year old should be much more mature than an 17 year old and so on.