Detailed Mirrors Graphical Quality Issue

Hi. I am here to ask about the graphical quality difference between the side mirrors, and the rear-view mirror. In some cars I have seen a major difference between the 2 types of mirrors. Let me show you what I mean.

(Demonstrated with a 240BX DX Coupe (A))
This is with the Detailed Mirrors at 512 px Resolution (0.8 detail and 256 m distance for both tests. Both tested in Safe Mode.)

See how crusty the Rear-view camera looks compared to the side mirror?

Now 1024 px Resolution.

The rear-view mirror looks better, but it is still a little blurry, and the side-mirror was already great looking at 512 px.

As you can see the lower resolution looks great on the side mirrors but falls apart on the rear-view mirror. Now I don't expect perfection (especially with my PC stats), but it would be nice to see an improvement to the rear-view mirror. I'm thinking 2 resolution sliders, one for the side mirrors, and then one for the rear-view mirror, to help with the quality without unnecessarily rendering the side mirrors at a higher resolution, saving precious frames while providing better graphics. Would this, or any other fix, be at all be possible?

And while i'm at it. Why does this happen in the first place?
--- Post updated ---
Updated Pictures. I accidentally put the 512 px test image in there twice instead of the 1024 px test image. Plus some minor readability and spelling edits.