So I was building a character for 4th edition with the D&D Insider Character Builder and found that my AC was a little off, looking more closely I saw that the Character Builder was giving me +8 AC for Scale Armor instead of +7. Double checking the Player's Handbook I found that it is indeed +7, though when looking at the D&D Insider Compendium I found conflicting information.
Description: Overlapping pieces of highly durable material, such as steel or even dragon scales, make up scale armor. Despite its heaviness, scale is surprisingly easy to wear; its straps and buckles make it adjustable and able to fit snugly on the body, allowing for flexibility and agility. Magic appears at higher item levels, and grants higher armor bonuses than its mundane counterparts. Scale armor grants +8 AC at levels 6-10, +9 AC at levels 11-15, +10 AC at levels 16-20, +11 AC at levels 21-25, and +13 AC at levels 26-30. Source: http://www.wizards.com/dndinsider/compendium/item.aspx?id=5
I checked the PHB Errata and the Heroes of the Fallen Lands Errata and found nothing mentioning this scaling of AC for mundane armors. Could anyone offer any insight into where this is coming from?