This item has been included in the 1.1.0-rc1 and rolled to UCD staging in preparation for production release.

Closing since QA has passed this one.

Yes, if the others pass then this one should as well.

QA ENVIRONMENT -
vista enterprise, firefox, ie7
smartsite-test sakai_2-5-x-test-073 - Sakai 2.5.x-R57934 gb2-1.1.0-a4 - Server sakaitest2

so, as of today, 323, 333 and 336 passed for me.
doesn't this pass, too? aren't they all sort of related?

Yes, broadly speaking this is exactly the behavior expected.

Basically the idea is that in "categories" mode, there are two options:

(1) Project Extra Credit = TRUE
(2) Project Extra Credit = FALSE

With (1) the instructor is saying that she wants to see extra credit contribute to the score ONLY as much as it will once all grades are entered. So if the total non-extra-credit points in a gradebook are 100, and you enter 5 points of extra credit, the percentage contribution of those 5 points will be +5/100 = 0.05

With (2) the instructor is saying that he wants to see extra credit contribute EXACTLY the number of points that are entered. So if only 1 non-extra-credit item (with 10 points possible) of the above gradebook is graded, then the percentage contribution of the 5 points extra credit will be +5/10 = 0.50

In "weighted categories" mode, the impact of "Project Extra Credit" is similar, but it has a substantially different impact on scores if you have an Extra Credit category with more than one item in it. That is, when "Project Extra Credit" is TRUE in "weighted categories", it means, assume that the extra credit contribution can be for the whole category weight even if only one item is graded. If "Project Extra Credit" is false, then the extra credit contribution will be bounded to the % grade for that item.