I'm painting our front door with BM Grand Entrance in High Gloss and can see scratches in the finished paint. I've sanded the door down twice using 220 and 320 grit sandpaper but it still appears in the final coat. This time I'm planning on using 400 grit in addition to the others. Usually 220 is enough to hide scratches with latex, but not sure why I'm still seeing this. Any idea how I can be sure this won't happen again? The depth of the scratches are unnoticeable during the sanding phase, even after cleaning the door with a damp rag.