Again people RIAA will certify the album as having sold 1 million copies which it had, but billboard will not let it chart as it does not represent consumer interest which is what billboard is about...

RIAA - how much product you moved, this is why they certify albums based on shipment cause thats how much the label/artist has moved(artist to store)

Billboard - consumer interest in the product, why 5 copies by one customer is counted as one, they look at the movement of the product over the counter(store to consumer)