For completionists who want S on Imoogi: you get one roll on knowledge per full completion of LoMl questline during Gangcheol quest turn in. Fortunately if you don't get S first time you don't have to erase knowledge during next runs because the roll can upgrade existing knowledge.
Thank you for this info as i was really wondering as it seemed to me the boss blitz fight was not upgrading the knowledge. Do you know if it works the same for Jang Iksoon? Because I finished the Loml questline a second time and it never upgraded. In fact I'm really not certain where I got the knowledge the first time, I never noticed it until after I got it. If it works the same it would mean then that you're not certain to even get an upgraded knowledge every time... I just hope he's not one of those where you need to delete knowledge and hope for the best on a fresh knowledge gain...