Don't beat yourself up over it. I've had multiple regional interviews. Each company is a little different. My first employer collected the logbooks at the beginning of the day and scrutinized them all day long. They were returned to us at the end of the day. At other interviews, they took a quick glance, shut the book, and started asking other questions. As others have said, just make sure it's as neat, organized, and legible as possible. Part of the good 'first impression' thing.