The oval head screws actually stick out the same amount with or without the countersunk washer, since the washer is countersunk past the bottom so that the screw goes in the same amount either way. I thought about your smaller screw idea, but the factory finish around the holes wasn’t clean and finished enough (some were a bit ragged with minor chips around the holes) for a smaller screw to cover the edges of the finish completely. I needed a bit of overlap to cover everything cleanly, hence the washer.
Without the washer, it would have taken a larger-than-factory screw to fully cover the finish edges around the holes. This way, I can use a factory size screw and not alter the holes in any way. I wanted everything to be totally reversible. If I wasn’t so persnickety, and the finish around the holes was cleaner, I would have just hit them with a blue sharpie and left them open, but my personality would never allow me to do such a thing, lol! Way more than any of you wanted to know, I’m sure!