Yes and the "justice system" gets even sicker than that. If an innocent person is in prison convicted of a serious violent indictable offence (GBH, rape, manslaughter, murder etc) and insists he/she is innocent then they will have to serve the entire prison sentence (despite having a history of good behaviour in custody), whereas if they admit to a crime they didn't commit and express remorse they will be released from prison years earlier.
Thats not an absolute, but yea acceptance of guilt does has a heavy weighting with the Parole Board and maintaining innocence will make it much harder to get released. It does lead to terribly perverse catch 22/loopholes for innocent people wrongly convicted.