In the raw refinement tool, exposure is adjusted automatically (or you can do it manually).  When you do things like increase exposure or use the ODR tool, you "brighten" parts of the image and when you do that, it increases the equivalent ISO.  For example, if you shoot an image at ISO 125 but you end up having to increase the exposure to double the brightness of the original shot, that's the equivalent of shooting the same image at ISO 250.  And so on.  If you brighten the image some, and then add some ODR to increase the brightness of the shadows, the two are additive and increasing the exposure will add some to the effective ISO, then the ODR may add (or even subtract) to/from that.

If you have an ISO 125 image and you get "pushed to 320", it means that on average, the pixels in that image had to be boosted by 2.56 times in order to get to the final developed image.

Regards,
Mike