When you modify the default Endpoint Security:Threats detected in the last 7 days report, the numbers for the total are different between hour and day as the time unit.

For example:
For a two-week period, the total shows 4844 detections when Day is used as a time unit. If you change it to Hour, the total drops to 1300. The actual data points in the graph are only from the shorter date range and not from the whole two-week period. Chart type selected is Single-Line Chart.