I totally agree. understanding how metal reacts is key. i see way to many guys coating stuff then getting out their pecking hammer after each coat...it's not guide coat! or they'll find a stretch and shtink it before working dents out properly, which will usually tighten it back automatically. I've tried both ways and when you properly work the metal all you coats will be thin, which means less pinholes underneith.
I notice when I try to half arse the metal work I will over work myself in filler, and remember, there's no dust fixing metal. I've also noticed I too will be pecking away between coats and at times just to get it right you will be taking away some of the true shape.
so take your time in metal. you can shrink it, stretch it, bend it, and cut it. in practical terms when you pull up a dent you should already know where the brow is that surrounds it. you want to roll your metal out not just yank it up with your pins, this is NOT how you fix it right. what i mean is push your lows up while you are pushing down on your highs. the damage is like that cause it reacts to impact like a drop of water in a bucket. the general rule is work the dent in reverse order of how it occured.