I looked at the same screen for scans that I typically do and, except for language and inch/mm , the only difference I see is that you have selected 48 bit color depth and I use 24 bit. When I try to scan to Photoshop Elements, I get a warning message that it can't handle it unless I "flatten" it. There's also a comment that some software doesn't work with 48 bit color.

I'd suggest you try your scans with 24 bit and see if they look better. It's unlikely your eye can distinguish the color differences anyway, even if your monitor can. It's possible that when David's sotware reduces the size of images submitted larger than 300 bpi, it has some problems with 48 bit color and your result looks fuzzy or out of focus.

Let me know if this makes a difference.