em10 the link you gave refers to the old system where an offender was sentenced to a specific number of years , under that system an offender could have been given 15 years but get out in 8. The new system is made to get over that, an indeterminate sentence means the person will not get out until the authorities think they are no longer a threat. Even when they do get out as the sentence was indeterminate , it effectively never ends . If they re-offend they can be put straight back in jail without a further trial, under the old system once they were released that was it sentence finished, so if they re-offended they would have to be tried for the new offence . Also remember that a new trial could not mention their previous offences so the chance of getting off are much greater.
The newspapers report these stories by quoting the 'review date' as though it were a release date because it generates more indignation, as has been illustrated here. If they told the truth and said that he would probably serve 15 to 25 years and still be liable to recall at any time , it would not be as 'newsworthy'