First run of Database Organizer for IMS for z/OS (DBO) converted reorg utility showed marked increase in CPU and Elapsed times.
Making recommended changes improved performance (EXCP and CPU time) to an acceptable level; UNLOADFILE=Y and no SAFETYNET and no DETAILREPORT
Recommended fine tuning is dependent on each environment. It is also based on database design, and dependent segments.
In this case it was a HDAM OSAM file with an Index, with many dependent segments under a small amount of root segments).
There were 35,000 Root segments, with 36,000,000 dependent child segments.