[mst]

Why is the vignetting score based off of the camera's jpg instead of the raw file ?

It's simply less work. You need to set a baseline at some point and use it as a reference point for the system. In terms of vignetting, we decided on using the standard JPGs a camera produces, since they can just bet fed into Imatest without any further work.

RAWs would need to be converted to JPGs first, with a defined set of parameters to have comparable results. That's actually the same thing a camera does already, so why invest more work than necessary.