Contrary to the table, you can't take that feat more than once. It's an error. Note that the feat doesn't contain the special language for being able to be taken more than once.
It was errated. Though it is funny to imagine an epic artificer who has four copies each of Extraordinary, Legendary and Exceptional Artisan, who pays none of the GP cost for item crafting, none of the XP cost, and has reduced the crafting time by 100%.