From several articles that came on June 07, 2011 I chose these to have a look at:
Troubleshooting when srvctl can't start RAC instance, but sqlplus can start it [ID 844272.1]
Unable to Manage the Manually Configured Listener with Oracle Restart [ID 987825.1]
it is the problem of standalone GI 220.127.116.11, not 18.104.22.168
Things to Consider Before Upgrade to 22.214.171.124 Database Performance [ID 1320966.1]
it contains references to 5 notes for recommended fixes not included to PSU:
NOTE:10259620.8 - Bug 10259620 - Wrong results with DESC indexes
and OR expansion
NOTE:9776940.8 - Bug 9776940 - Wrong results from projection pruning / ORA-600
[qkeUnreferenceExpr_2] parsing SQL with expressions
NOTE:11719151.8 - Bug 11719151 - SQL Plan Management capture causes slowness
NOTE:9842771.8 - Bug 9842771 - Wrong SREADTIM and MREADTIM
statistics in AUX_STATS$
NOTE:10336129.8 - Bug 10336129 - Solaris: Poor IO performance
on Veritas for 11.2 compared to 10.2
I believe it is always worth to review patches that already came even on top
of PSU for release you are going to upgrade to, especially if fixes related
to wrong results of queries.
Mount Options for Oracle files when used with NAS devices [ID 359515.1]
it is very often needed document to compare NFS mount options with certified parameters.
Have a good day!