Incorrect Item ID / powered comparator is unpowered_comparator:8

I'm not sure if this is something that Mojang intended to do, but the ID for a powered comparator is minecraft:unpowered_comparator [metaValue]

Facing North, the meta value for a truly unpowered comparator is 0. However, as soon as it is powered, it turns into 8. If this is not a bug, will Mojang making the ID for a powered comparator it's own? Repeaters currently have their own ID if they are powered, so why don't repeaters?