Each state will have a formula in the legislation. In WA for up to 6yrs it used to be 2yrs parole, 2 yrs remission and 2 years in jail. Longer sentences had a different formula because I think either parole or remission was a maximum of 2yrs which affected the time served. So basically anyone getting a 6yr sentence would only serve 2yrs in jail.
I agree when it comes to parole it should be a lot harder to get. My wife was a bank teller involved in an armed robbery and the 2 scum involved were on parole and had 5 parole breaches between them on previous stints yet they kept getting let out because they would do the courses and say the right things to the parole board and then continue on their merry way.
Remission is different. Working in a prison is a horrible job and you need a carrot to help make it a bit safer. When you work there it's a different world and you have to be able to get on with these scum and put your own prejudices and beliefs aside.
Personally I think life should be life and with pedophiles they should be castrated or put to death. Not everyone will agree with that but the damage they do is worse than murder in my opinion. Most murderers it will be the first crime they have committed (serial killers, sociopaths and psychopaths aside) and they tear themselves apart with guilt over what they have done.

