VirtueMart not allowing me to deselect "override" within price screen

[deebd]

I am new to VirtueMart and seem to be having a major issue on the pricing section. I have several options or rather sizes for each product, and have tried to deselect the "override" option within the pricing screen, however it will not allow me to do so? Any help here is greatly appreciated. I am running Joomla 2.5.7 stable and I believe I am running virtueMart 2.0.6 with php 2.09c stable.

Thanks in advance,
Dee