I'm not sure what your question is. But if it's about where the info from GoS is from, and why it's not on the online translated version of Zhou Yu's bio--well, the Zhou Yu bio at KMA doesn't have the Pei Songzhi notes, from which the Jiangbiao Zhuan excerpts may be found.
When you talk about a SGZ bio, it would be best if you indicated whether you mean the original Chinese version, or one of the translations published online. I know there are some bios out there that are incomplete, with translators skimming over sections they don't understand (or omitting them, even) and ignoring the Pei notes, and some bios may contain mistranslations (hey, we're not pros). Therefore, it is good practise to be precise where you got your information from so you don't sound like you're blaming Chen Shou or Pei Songzhi for something that they didn't do.
"Whatever you do, don't fall off the bridge! It'll be a pain to try to get back up again." - Private, DW 8