There isn't a huge amount of difference between Cream's arrangement and Tull's subsequent arrangement. Not particularly surprising as many British blues bands (and that is what Tull started off as, beit belatedly) ) borrowed freely from each other, once someone had created a good electric arrangement to rip-off. How many bands played Crossroads a al Clapton rather than base it on the original Robert Johnson version (btw labelled composer as 'traditional' on my Robert Johnson compilation CD)? Cream themselves ripped themselves off, e.g.  Oh Lawdy Mama became......??? Probably the most ripped off song was Elmore James' Dust My Broom - can we blame Jeremy Spencer of Fleetwood Mac for starting that? Canned Heat when they weren't boogying, regularly "updated" 30's blues for their own purposes. In fact when Taj Mahal appeared on the scene, there was a  collective breath of relief with somebody  appearing to do something original with old and new blues - in truth Taj had a knack of taking the old blues 'back to the country'.