Just wondering if theres anything that might be of a disadvantage if you run multiple game servers off the same ip and different ports?

If it is all going to be hosted on the same server, it is not going to make any difference technically.

I came up with an analogy to explain this to someone less technical one time...

Using different IP's and/or ports is like having multiple gates to your backyard. It doesn't matter which gate you use, it's the same yard.

The only minor issue (actually inconvenience) is having to type the port number when connecting via the game's console. Other than that, nothing different.

i didn't think it would matter. thanks though

No, it doesn't usually matter. Because people rarely memorize IPs. They usually:

1) Find the server in a server browser
2) Click a server link on a web page
3) Copy and paste the server link from somewhere
4) Have the server in some sort of favourites list