What exactly are the semantics of time series graphs specifying 'Week'?

[starbuxman]

What exactly are the semantics of time series graphs specifying 'Week'?

I have a time series graph that has data like:

12-22-2007  7
12-26-2007  6
01-12-2008  4
01-15-2008  1
02-22-2008  2
02-15-2008  1

etc..

and i expect that the time series graph will interpolate the values and show me a point per week

It doesn't seem to do that. In fact the data is so far from what I wanted that I'm now a little concerned as to why the option to choose 'Week' is there. I get valid data (at least) by specifying 'Day' but then the graph shows me points at a sub-week scope, which is inappropriate. I want one data point a week.

Am I missing the boat on this? How is it supposed to work?

Thanks for any and all help,
Josh