Digital Deluxe Upgrade vs Digital Deluxe Edition?

So a pal of mine has noticed that on Origin, you can purchase the deluxe eidition of ME3 for £34.99 however it is cheaper to buy the normal version for £6 and then upgrade it with the deluxe edition upgrade pack for £5

Of course, i would prefer that considering it's cheaper but are there any differences between the upgrade and the deluxe edition? And is the upgrade even designed for the normal version?