According to RDS, Bute's clan offer a more lucrative offer to Kessler after the the lame step down from Pavlic. They knew the negociation with Stieglitz were not going smoothly so Bute's clan tried to reach an other agreement with Kessler, offering more money. http://www.rds.ca/boxe/chroniques/324723.html
He probably didn't "turn it down." There's a reason why they're on the same date. They're likely building this into a mega fight.
Ward refused to fight in the tournament unless he got all his fights in his home town! Ward refused to allow Bute to fight in his own personal tournament also. Ward won a fight with an illegal head butt! Where is the rematch?!