"Modified Product/Service" is not very informative. It would be great to know what exactly was modified, i.e. the next due date was updated or 'do not suspend' was set. This would let the supervisor know, which specific action was carried out by a particular staff member.
+1 to karma for voting :)
Thanks for your feedback. WHMCS now lists exactly what was changed in the logs when modifying a client or service.