An umpire's understanding of the game advances in fits and starts. It's the experience of working the games, of living through the plays, the calls made judging the outcome of the plays, and the reactions of coaches/players/fans to the judgment calls. This is the well-fertilized ground in which an umpire grows.
No umpire was ever born. He didn't pop out fully formed. No umpire was ready for the big leagues the day after he started in the little leagues. It's commonly called "serving your time and paying your dues." It's the process every umpire endures on his way from the first game he calls to the last game he ever works.
Along the way, he will use different rules and better mechanics. That's a good thing. On the other hand, certain rules and mechanics can bedevil an umpire's development. His progress can hit stumbling blocks.
This article starts with one of the stumbling blocks Jim Evans conquered, 6.06c. Then with a couple of observed examples, I'll suggest that the 6.06c Approved Ruling could get better.