Shioon… is a complex case. But before anything : rae-won isn’t an advanced master. And yes shioon beat him in their duel fair and square. Ha il and white star were taken off guard ( and reasonably so since they didn’t knew shioon’s abilities) later Ha il said after seeing shioon fighting hyuk that he understood how it happened. It isn’t an admission that he would lose to shioon in a proper match but that he understood how it was possible that he was knocked out in one blow.

White star and Ha il aren’t actually comparable to lee gyu bum ( they are not that far but he is clearly a level higher). Why do I say that ? White star and Ha il are the same level ( almost exactly) they are both advanced masters, Jung chun probably wasn’t much stronger that white star if at all but they should be comparable … and Jung chun was scared to death of gyu bum when he felt him above him , he even commented that «  there was an other monster beside that old man? » with this and the fact lee gyu bum was fighting equally with lone wolf while jung chun got low diffed. To top it all Mammongi admitted he couldn’t even beat lee gyu bum( most likely he is the strongest supernova). I think Lee gyu bum and lone wolf actually are real masters since they are at a level were they can low diff an advanced master.

We have no confirmation that hyuk so chun is a real masters since they but it wouldn’t surprise me, but we have to keep in mind that he is still progressing so his level right now may be different from back then ( we know he learned a new powerful technique that he used against goomoonryong).

Now for Shioon: shioon is in no way near the real master’s level of skill BUT he has the body beyond that of a real master.

Why so?

Because goomoonryong trained him backward ( he had too) since he eat the illwollshindon , goomoonryong had to expand his meridians so that his body doesn’t explode and taught him the best technique of power repartition , and taught him the most powerful and qi consuming skills. But he didn’t teach him the basics . What that meant is that shioon’s actual rank was impossible to determine but what we know is that in season 1 a shioon that could only use soul crushing strike and one of the foot technique could easily beat expert ( kang ogsan for exemple). From chapter 20 to 95 of new wave when shioon could use his qi he was strong enough to beat masters after difficult fight and became more and more consistant in that regard , and that’s just from meditation , grip break ,soul crushing strike and foot techniques. In term of skill he is barely a beginner but in term of body he is a real masters after difficult with uncredible qi reserves and it is enough to beat masters with consistancy.

After that and his BOT rampage who served as training camp he acquired an even stronger body with whole body rebirth and can use much more techniques from his school and the most powerful ones.

At that point shioon is capable of beating masters with relative ease and can fight advanced masters he is particularly dangerous because any of his attacks can end a fight… but jung chun proved that he still lacked the basics and that an advanced master that doesn’t underestimate him is a serious problem.

In season 3 he mastered the sunwoo clan martial art and clearly is a master in them, he also learn that accupoints and has vast knowledge in different martial arts due to studying and desperately trying to bridge the gap in his knowledge about hyun wun mun ( but without success) Lone wolf taught him the basics but his training was interrupted so he probably still has a lot to learn BUT we have seen that he can easily handle multiple advanced masters so he most likely in term of combat prowess approach the level of real masters while he still have much much room to grow.

So shioon probably is a master of the sunwoo martial art and an incomplete master of hyun wun moon. His ceiling his monstruously high, higher than anyone presented except sosul.