Dart rear quarter style lines

But was it blocked properly? Body work is only done with 80 and 120 grit to finish flatten and shape panel filler after metal work is completed. Blocking with 120 / 180 / 220 ...400 etc is to remove successive sanding scratches for
paint. 180 and finer will just follow waves and can ruin body lines / edges if done poorly or aggressively.
Pick your body shop carefully.
...or do it yourself.