Promoting users of the same level

For the website I’m building I’ve altered user roles conform the purpose of the website. Since the editor account now has permissions to promote users that role can effectively change roles of the website members without the admin needing to do it. However, it seems that it can’t promote to an editor as well.
Would this be a remnant of the deprecated levels? Editor would then be considered level 7, but if I’d put say the Author to level 7, then the Editor would no longer be able to promote a user to Author.

Does anyone have any hints or tips to how I can accomplish the Editor to promote other user to editor as well? Thank you in advance.