Auto ISO Range on K-5iis in GREEN mode

Hello, I have recently purchased a K-5iis as an upgrade from a *istD.

I notice I can set up the  auto-ISO range in the settings somewhere which applies correctly to modes other than GREEN.

However GREEN always seems to be 100-3200, irrespective of the range I set up, and I was wondering if this is how it works, or whether there's a bug in the firmware?

I'm guessing the former, but seek clarification from anyone who knows.

Apologies if this is covered elsewhere: I tried searching but to no avail.

Also in Green mode, it seems that using an external flash in low light conditions doesn't encourage the camera to change the ISO to anything lower?

Thanks