The downfall with trying to show qualifications that would separate an E4 v. E5 v. E6 for example- is that it would be nearly impossible to layout as they are not hard and fast, boxed rules. You might interview and show an E6 level in Behavior, an E5 level in Design, and an E4 level in Coding. You might have a highly unique skill or speciality that would solve a massive problem or gap on a specific team, so from a technical standpoint thats E6 level but behaviorally and scope wise, you operate more at an E4. So the team might elect to post a range like $185-$240 to cover their bases for the right candidate.