Continuity mistake: Dean drives the Impala to the coroner's house at the same time Sam is driving Castiel and Jack back to the bunker, also in the Impala. (00:31:15 - 00:33:45)
Continuity mistake: After Dean zaps the TV with the remote, he lowers his right arm. The next shot behind Dean's right side shows him lowering his arm again.
Continuity mistake: When Jack tries levitating a pencil, the pencil completely vanishes after he sets it down again.
Answer: Angel blades come from angels. It's their angelic magic that makes it special. Therefore, an archangel blade is made magical with the powers of an archangel. They couldn't have just created one or used one, as none of them are archangels.