hiding frames from UnitAura

[ObbleYeah]

Hullo, i'm building a simple function that will display a filtered list of important auras on my raid frames:

http://abload.de/img/screenshot2014-11-30ay0d0z.png

This is the code i currently have:

https://gist.github.com/anonymous/dda27accffef2b17ce43

Now, the auras I want to track will successfully show when they appear on the unit. But they won't bugger off again when it's dispelled or the duration runs out, as you can see in the picture above. I assume i'm just getting the logic wrong on in terms of when to show/hide, but the right method is eluding me today can anyone help?