I got it working (for the most part), without needing to use the dirty variable hack. Basically I make sure $1- and the edit box are the same. If they are, that means TAB isn't trying to auto complete.
The Downfalls:
It still takes out any extra spaces in the edit box string
If you are use the normal auto complete on a nickname and its the only auto complete match, and its the last nickname seen, it will toggle between that nickname and the channel if you hit tab again. (not a huge deal)
But now you can tab through multiple normal auto completes and it won't change to the channel name if one of the nicks is the last nickname seen.