1) Exactly one-year after their debut match in that match-up.
2) The point where they had their lowest career win rate in the match-up after having one-year's worth of experience.
3) The point where they had their highest career win rate in the match-up after having one-year's worth of experience. If their win percentage never has a moment where it drops below the initial starting point, the win percentage and date from the start will be recorded instead.
4) The last ever game they played in the match-up, basically their final career win percentage at the match-up.
I used TLPD for the records, which is a great source of information, but unforunately is by no means complete, especially for the earlier years of professional Brood War. I chose TLPD over the database provided by YGOSU because TLPD differentiates professionals from amateur players (that these players played against in tournaments such as WCG). TLPD's records for the three players in question are not totally accurate because it fails to take into record the last ever offline qualifiers for Tving OGN StarLeague, the match records for which are no where to be found in the YGOSU database as well.
In case you don't believe me, this is one game from those offline qualifiers (2012-03-31) where Bisu beat Bb.yong 2-0, before eventuallly losing to RorO 1-2, which is why Bisu wasn't there for the last ever OGN StarLeague.
+ Show Spoiler +
So Bisu's records (Flash and Jaedong did not participate in this qualifier due to being seeded) in the offline qualifiers will be added in, which will make Bisu's overall career win rate in PvT and PvZ slightly different from TLPD's records in case you wanted to check the numbers.
Flash was always beast-like in the mirror match-up, except for a brief window of time in 2008 when he could be taken down by rivaling terran players such as Firebathero, or ForGG. 2008 as a year, despite giving Flash his first ever championship title, was not that fruitful for Flash in terms of developing as a dominant player. Flash recovered his 70% career win rate in 2009, but reciprocated between being above or below 70% for quite some time, before securing that thresh-hold for sure by the end of 2009, and keeping it that way until the professional Brood War ended.
Flash was famous for being the "Bionic Genius" during his amateur days, and lived up to the name with great results versus the zerg race initially. However, he hit a rough patch in 2008 when he kept losing to numerous zerg players such as GGPlay, Jaedong, and Yellow[Name]. He recovered from the rough patch, and with the help of some meta-game revolutions that FanTaSy discovered, raised his performance against the zerg race to heights he never reached previously, before having his peak cut prematurely due to the end of professional Brood War. From mid-2011 to mid-2012, Flash was able to maintain a career record above 70% for more than a year.
Flash never had a point in his career where his overall win rate went below the win rate presented at the chosen starting off point of early 2008, and had slowly raised his win rate until it went above 70% for a moment in time in 2011, before settling at a career win rate of 67.85%. Terran-versus-protoss match-up was the only match-up Flash failed to maintain a win rate above 70% by the end of his career.
Jaedong started-off with relatively humble beginnings, having a good, steady performance during the first year of his career, but nothing mind-blowing. He then picked up the pace massively after a rough start to 2007, his break-out year, and finally hit his career peak after dismantling Flash in dominating fashion in GomTV MSL Season 4 round of eight in early 2008. His career win rate would not deviate too much from that point on.
Jaedong showed his promise in the mirror match-up from the get-go, and wouldn't slow down one bit, until he dominated the match-up in an unprecedented fashion with an insane career win rate of 80.0% in mid-2009, making the most out of the masses of zerg-versus-zerg match-up the previously unseen scheduling Shinhan 2008/2009 ProLeague provided. He would slowly lose his iron grip over the match-up over the years, losing numerous key best-of-five series to rival zerg players such as Calm, Hydra, and ZerO which severely limited his chances of expanding his trophy case, until his career win percentage dropped to a more mortal number of 72.69% by the end of his career.
Jaedong wasn't a player known for his zerg-versus-protoss abilities initially, but he started to pick up the pace when he starting to win titles left and right in late 2007, and eventually hit his peak in 2010, when he had that 15 game win-streak versus the protoss race. His career win rate would only go above 70% for a brief moment in time before settling on a career win rate of 67.83%.
Bisu, back when he was a rookie, was a protoss known for exceptional macro-management. He started to have a terrible down-swing in the match-up, plummeting his record to 55.65%, which was incredibly detrimental to his individual league career considering this was when Bisu was making it furthest into the bracket stages. Bisu was frequently being knocked out of various tournament at the hands of terran players such as Mind, Iris, Flash, and ForGG. He would slowly recover his numbers with great ProLeague performances over the years, but his best days of protoss-versus-terran prowess was cut short by the termination of professional Brood War.
Bisu had excellent results in the match-up even before his fateful finals versus sAviOr, and would raise his results past 70% in 2007, but struggled to keep up with the adaptation made by the zerg race by the end of the year, and hit rock bottom in 2008, showing signs of a failed transfer by SK Telecom T1, before striking back with a vengeance, and recovering his excellent record versus zerg record with good ProLeague performances.
Bisu wasn't a natural at the match-up to begin with, but starting with the golden era of the "Six Dragons" that began towards the latter half of 2008, when all the top protoss players would dominate the top placements in individual leagues, Bisu turned it all around, proving himself to be the king of all the dragons with superb results in the mirror match-up. He would thwart numerous attempts from wannabe leaders of the "Six Dragons" such as free, or JangBi in multiple best-of-five series, and kept up the pace in the ProLeague also. He may have lacked individual league performance, but kept providing good results in the ProLeague to retain his career win rate of 63.21%.