Have you ever had this struggle when try to wet sand paint completely flat? You’re wet sanding for what seems like forever, and no matter what you do, there always seems to be an ever so slight amount of texture left? It might look like ripples, and very very subtle orange peel. Yes, it's getting pretty detailed, because this problem is usually really hard to see. But that's the difference, making sure these subtle issues are gone.
Here's the problem, there's a good chance this issue isn't even in the paint. Even though the clear coat is sanded as flat as it could possibly ever be, you will still see texture from under it. This means, that problem you're chasing, might be too late to fix.
The point is, not only does the clear coat need to be sanded flat, but just as importantly, the primer needs to be sanded completely flat. Be fanatical about block sanding the polyester completely flat. It always looks great, until you can't figure out how to get the clear flat. True Blox play a key roll in making sure polyester is completely flat, with 100 grit. This is especially a problem in any concave areas. So, when doing body work and sanding primer, be more aware of making sure the polyester is genuinely flat in these areas.
Please, do not use this as an excuse to let mediocre wet sanding pass. This is simply saying, that texture from under the paint can and will show up through the paint.