I've done several of these before where I have multiple conditions, but I've never gone above 3-4 I THINK. Maybe post the statement, & we can take a look at it...
Usually when I do this, I'm checking
<0
=0
>0
Here's a sample of one I have in the stuff I'm working on right now...
=IIf([est_diff]<0,Format([est_diff],"Currency") & " Under",IIf([est_diff]=0,"Balanced",Format([est_diff],"Currency") & " Over"))