New poster. This is a really great site.
I was trying to apply the rules in the DMG to create some new 4e monsters. To check my theory on what was in the DMG, I tried to verify the rules to the monsters in the MM. I could not reproduce the AC and Defenses.

Are there any hard an fast rules for these characteristics or do the rules get one close and then adjust for roll, type, style, or flavor of the monster?
Thanks for any help.