As of v10 the points system does actually allow calculating results within a range, so the problem of calculating "points earned in week" isn't serious, it's actually the issues around storage, configuration, and display, that are the problem.

The way v10 does it is it does a (good) estimate of the points earned at a certain point in time by looking at the tallies and then subtracting what it knows wouldn't be in those tallies at a particular further point back in time (as it does have that data logged in different tables indirectly).