The 'from' 'to' date filter on the circulation statistics wizard are exclusive, but should be inclusive. Example 1: Period: check, filter from first day of month to last day of month Patron category: check Example 2: Period: check Group by: month, select month: same as above Patron category: check These numbers can be different as the first and last day of the month are excluded from the first query. My guess is that we query with between date1 and date2 without using the date() function to ensure the results are correct for the timestamp/datetime field. Verified in 3.22.10 and 16.11.0