Davis always did the scheduling. It was in his contract he signed under Bump.
Davis refused to upgrade the schedule. As the story goes, at the annual end of the season meeting after the '98 season, Bowlsby tried to take the scheduling away from Davis & Davis threw his contract in Bowlsby face. That incident along with a few other things led to Bowlsby's decision not to renew Davis' contract.
In '98, Indiana & Iowa finished tied for fifth in the conference with 9-7 records. Iowa won the tie-breaker and got a first round bye in the BTT. Indiana beat Ohio State in the first round & lost to Purdue in the quarterfinals. Iowa got blown out by eventual champion Michigan in the quarterfinals.
Indiana finished 20-12 & made the tournament. Iowa finished 20-11 but did not make the tournament because of an awful non-conference schedule. The '98 team became the first Big Ten team to have a winning conference record & not make the tournament since the expansion to 64 in '85. I think it has happened since but I am not sure.