So their sync rates varies a lot...

Maybe in their previous life Woojin's sync with Haesol was really high cause they felt comfortable around each other, maybe not romantically but just comfortable as friends while with Jaechan there was some sort of misunderstanding making Woojin uncomfortable around him even though he liked him.
Now he doesn't really know Haesol cause the way they met changed and Woojin doesn't really feel comfortable around her, and with Jaechan it's rising cause Woojin is starting to trust him more making their bond stronger. Of course the wavelenghts in guiding are the most important part, but the bond between esper and guide can affect their sync rates apparently (at least in this one story)