It's a SetiQueue-message that shows up I think then the lower limit is calculated to more than 50, since this is the max override-value.
The max upper limit is 800.
To disable the limits, goto the user.1234567-directory, edit user.ini and set
User/Insane=TRUE
Then this is done, you can use your own limits. With multiple users, this must be edited for every user that needs it...