Purging concurrent programs

We are trying to use the Purge Concurrent Request and/or Manager Data Program Purge for purging the concurrent request logs but not sure about the Age parameter . As per Oracle document this parameter is for number of days the logs will be kept but does that mean it will delete all concurrent programs before that date or only programs which are in completed normal state. I am asking this because in my scenario, I have around 40 Lac concurrent requests submitted on 20th Dec. where as out of those 20 Lacs are in completed status. Now I want to purge the requests which are completed to improve the performance but not sure