Federal inmates must serve 85% of their sentence (6-12 months of that can be in a CCM or "halfway house"). The only reduction in time is through RDAP (if eligible). The date on the BOP website is up through CCM. Supervised release is the time period after the release date, which can be found on the inmate's Judgment and Commitment paperwork.
https://www.inmateaid.com/ask-the-inmate/so-i-have-a-release-date-on-bop-website-is-this-the-actual-date-and-does-he-get-some-kinda-paper-work-on-that-and-if-so-when#answer
Accepted Answer Date Created: August 26,2013