I under stand, however if you have followed threads regarding refinishing here, you need to consider some of the "variable's" that are part of "refinishing".
Different clears or single stages cure and compact (become more dense) than others.
Then there is the issue of, if the paint is catalized or pure air cure.
Type of reducer used, and what was the temps, the humidity, as these will often create a different "hardness" in the paint substrate.
Some paints just cure out different and can cure quickly or take a longer time.
So, how long was it since it was applied, etc.
Then it can move on to the brand of sanding paper or disc, and actual grit size, as some are more "exact" in the grit size than others.
Are you going to "dry sand" or "wet sand"?
How can you know that the amount of pressure you will be applying,either by hand or with a DA, in regards to what someone else offers up as their experience?
Which is why the use of an electronic paint gauge is so important so as to not strike through the paint film.
Hope this helps you.
By the way, a mil of clearcoat is not near enough to contain enough UV blockers in the paint film to start with. 5 mil is a little excessive and may create crazing later in the life of the paint film.
The "safe" thing is to understand that only the top 1/2 of a mil of clear is the part that usually contains the majority of the UV blockers and is the most "dense" portion.
That can vary as well, just so difficult to come up with even general answers.
If the vehicle is a "show car" or a "trailer queen" that spends most of it's life in a garage, away from the sun and elements, more clear can be applied to produce a '"deeper" gloss, and seldom will any negative results become apparent.
Unfortunately, many times this is not understood by most.
