I was of the impression that under 4E, each monster level had a base attack bonus, hitpoints, etc., modified by the monster's role. The way they made it sound, if you want level 15 kobolds, you just go to the table, look up level 15 to get the base values, modify them for the monster's role, and poof, you are done. Tweaking can commence as you desire, adding an ability here or there as fits your adventure. It's less formalized than 3E, but this new process was essentially what you had to do before 3E, but with better support for the underlying math behind player-character creation and advancement.
Hope This Helps,
Flynn