The times apply to the readings download, which is five-minute data and can start and finish part way through a day. Hourly flow reports only the hours lying wholly inside the period — half an hour of window cannot report an hour of water. Daily flow is per calendar day and ignores the times.
Raw parameters are the device's own 5-minute readings. Daily Flow is calculated (last totalizer reading of the day minus the first), so it arrives as one row per day on its own sheet.
Every Excel download carries an extra sheet with a chart of its numbers — a real Excel chart linked to the cells, so you can recolour it or paste it into your own report. Parameters measured in different units get a chart each, and each point carries its value printed beside it (on a chart with thousands of points there is no room, and the sheet says so). CSV files cannot hold a chart.
One row per day, one column per flow meter, for the period chosen above. Ignores the site and parameter selection - this always covers every site, and a site with more than one flow meter gets a column for each.
One row per hour, one column per flow meter, for the sites selected above and the period chosen above. Each figure is the totalizer at the start of the next hour minus the totalizer at the start of that hour, so the hours add up to the day — the same numbers as the Day chart. An hour is left blank when a reading is missing at either end of it. The hour currently in progress is not included until it has finished.