The two bulbs are in the same price range but it's the availability that seems to be better for the SP-LAMP-006. The dealers that carry the Toshiba lamp all show "back ordered"; except the ones that are charging MORE than MSRP.
It was also my assumption that since the two projectors are, virtually, identical, the bulbs would be the same. InFocus would have to have gone out of their way to make the bulbs different.