Hi Sal
It's not so much a per-requisite to maintaining them but SU25 does impact SU24 updates. The BRM does a check for the differences if SU25 has not been executed. You could probably update the PRGN_STAT table directly and avoid running SU25 to bypass this.
Some examples in SCN of this topic
SAP GRC BRM: Error SU25 Role Creation
GRC BRM TCodes of Role cannot be updated
In a nutshell - they couldn't complete the step Maintain Authorisation Data as SU25 was not executed for Steps 2A and 2B
Regards
Colleen