Given the length of what most federal offenders are actually serving, it would be extremely unlikely that they would get out on parole. Most people do not get parole on their first appearance. If you're going to have to wait another five years, then what is the point of participating in the programs to fulfill your correctional plan if you're going to wait until statutory release or warrant expiry in any event?
I think you lose the part of the incentive or the motivation that encourages people to prepare themselves for release if a progressive release system is not in place.