Deaths, not cases. One goes back 1 week same day to ensure the comparison is legit, but you still get corruption on holidays. Friday not compared to a Wednesday. Fridays compared to Fridays.
The people who do the counts don’t work weekends . . . all this sort of thing.
I read your post too fast. Thanks for the correction.
Many states are down to reporting once per week or just every other day. So the only reliable metric is the weekly totals now.