Most veteran PDR techs understand crowns, eye brows, high spots and trapped pressure. And then there are some who don’t. Dents in some cases don’t always appear to be a problem but looks can be deceiving.
Tapping down pressure needs to performed correctly. Some are obvious and some are not. Depending on the panel, you must identify how soft or strong the metal is. Determine what tap down you start with so you can prevent tap down mistakes. Here is a little video about where to look for crowns.