Don't want to update IOS with supervision

Hello,

Recently, I've been reloading a batch of iPad minis for deployment around our campus which is a Apple Configurator environment. At the end of my loads, I needed to access one of the devices and afterward, to reset the PIN and other settings on the iPad, I needed to "Refresh" the device. When I did this however, the device was automatically upgraded to IOS 7.

I was able to reset the machine back to IOS 6 eventually, but when I try to return the device to Supervision, the Configurator's option for "Update IOS" always grays itself out and reads "When update is available".

Is there a way to supervise a new device without automatically updating that device to IOS 7?

Thanks for any help with this.