Date Validation for Relative Date Range Setting

Hi,

A few of our reports apply the relative date range setting to pull performance results for campaigns that have launched in the last 7 days (see screen shot below).  A question was raised by one of our email marketing managers, asking two things:

1. What is the true definition of "last 7 days" when using this rule in a report  and

2. Is there a way to get a verified date stamp into a report that uses a relative date range rule instead of the copy that says " Sent Date Range is equal to/is in Last 7 Days"?

For example:

A weekly automated report sent results on 8/7/2017 using "last 7 day" relative date range rule and the report included campaigns that launched on 7/30/17 - 8/5/17.  What is the starting point for the relative date range rule to begin from (run date of the report or most recent campaign that contains performance data)?  Seeing as there's a 1-2 day data lag post campaign launch, it appears the system looks for the most recent campaign with data results and then applies the 7 day range.