"I keep a notebook in the truck and have documented all his errors over the last few months, so I will be able to pinpoint any problems to him (date/time, what he did or didn't do)."

That's perfect !!  So, many people don't document employee's performance and at a later time can't recall the date/time/specifics of the behavior's or actions.  Then the whole 'employee conference' turns into a interpersonal, "feelings and emotions" mess. Whch will turn into a personal "he just don't like me"  whizzing contest.