This is my understanding, so take it as offered:
When you turn in a result, your computer says something like:
I tested (k,n) and I started on mm/dd/yy hh:mm:ss and just finished it.
The stats server then spreads your work over the entire time period.
The longer it takes to perform a test, the worse that last 24 hour graph is going to look. It's delayed 6 hours already, and I'm not so sure that even delaying it 24 hours will really help.
What would make more sense (to me) is a last week graph with the most recent 24 hours removed (ie, 8 days ago to 1 day ago)