The main difference between :
pmrun -h <server> ksh
prmun -h <server> pmksh
is that pmksh is a Privilege Manager controlled shell. Execution of individual commands within a pmksh are controlled via the corresponding shellprofile and may be audited in the eventlogs.
Since ksh is a system shell, only the execution of the shell itself is controlled by Privilege Manager via the pmrun command. Individual commands within a ksh are not controlled by the Privilege Manager policy and are not recorded in the eventlogs.