If you mean “This week” – it does actually mean calendar week starting from Monday (you are the second person who is asking about that, so we’ll definitely add some explanation note to the settings in the next plugin version). If you need 7 previous days (i.e. 168 hours), then you need to select the “Last 7 days” option.
Hope that helps. Please let me know if you have any questions, or if I misunderstood your question.