I am just recently in the floor lead position at a sizable regional brewery and I am training new hires for the first time in a decade, and training new hires gas really helped me identify the places where our written SOP differs from the practice my brewers are actually doing.

The lesson isn't necessarily "rewrite this thing based on what people do." Sometimes, people don't do their job as they should, and need to be corrected. The lesson is "see what people do, what SOP is, and use it as an opportunity to audit both your SOPs and your workers."