Marcy's Law procedures?

[BillyKunstlerFan]

since in any given hearing, a commissioner will probably deny the applicant, how do you determine if you get the 3, 5, 7, 10 or 15 year delay? I mean I know it has to do with your likelihood of ever being paroled but does it seem kind of arbitrary. Like Doug Mowser, who never admitted to killing his stepdaughter, got a 5-year denial when I thought denying involvement leads to an automatic 15 year denial.

I might also add why there is a need for Marcy's Law - most of the ones you don't want ever to get out tend to receive LWOP anyways (interesting fact - before 1978, the worst you could get for any crime was 7-to-life).