SBF put a ceiling on the sentencing because he was very guilty, fully in charge, and showed no remorse.
Edit: it’s 54 days per year, not 90%
> The Act amended 18 U.S.C. § 3624(b) so that federal inmates can earn up to 54 days of good time credit for every year of their imposed sentence rather than for every year of their sentenced served. For example, this change means that an offender sentenced to 10 years in prison and who earns the maximum good time credits each year will earn 540 days of credit.
Here’s a 45 minute video if you really want to know more
I know the "85%" meme that HN parrots incessantly but that’s not the fully story (not sure why anyone would expect programmers to be experts on federal incarceration nuances… I only am after a friend wound up in federal prison)