Would it not be greatly dependant on how far the project gets in that initial funding. The projects that overshoot in the final days are generally ones that are 60-80% funded.

Yes - things that are U shaped would depend heavily on how great the initial and final funding is. In terms of $/t, rather than donations/t, it'd look more like - well assuming you got all your money on the first and last day you'd have two sheer cliffs with a perfectly flat plateau between them. But in reality it's likely to be somewhat smoother than that and the plateau is unlikely to the perfectly flat.

Assuming that the linear model holds until the last few days and then you get an upturn equal to the initial contributions, then you'd be looking at something like $22-23 million. Well, I'm just measuring it on my screen with my hands to get that, but that'd be my prediction based on what little I know of these sorts of fundraising thingies, assuming it behaves in the same manner as they did. ^^;