No that is the easy way. useing 1 300 and 400 just makes the script check the users list to see if the person has the level of 1 300 or 400. which is so much easier then making variables because with variables you would have to make a new one each time someone advertises. Which would need a bunch of cross reference checks.
it could use work but this was posted last year so idk it might have been posted many more times with more improvments
i would say that you need to remove the user when they leave the channel