Fortigate 600e date EOS EOL EOSL

You are correct, with caveat. With Fortinet it starts with End of Sale date - once it is announced, the End of Support is calculated automatically and  usually does not change any further. FGT 600E End of Sale was announced in October 2025, so it automatically sets End of Support date for it 60 months forward, i.e. it will be supported up to October 2030 (of course provided Fortinet don’t change their mind, but I can’t recall this really happening). I once wrote about it, sure official docs also have it too: https://yurisk.info/2023/01/03/fortigate-end-of-support-end-of-life-cycle/