The raw-converter generates a rgb-raster image that can be viewed on your screen or being saved to disk and opened again to be viewed. In both case the rgb-raster image is the source of the visible image. But in case of the jpeg-file it has been compressed and therefore has most likely
less blinkies. Assumed you're using the same converter, the same settings and no treshold.
That might be a trick that works. But only if you want to edit the file anyway. It won't be advisible if you shoot jpeg.
I don't know what more control an external light meter gives me, except with studio work.
I just learned that in the Nikon D810 and D750 a fourth metering mode is introduced, the highlight-weighted metering mode.
http://www.nikonusa.com/en/learn-and...ring-mode.html
George