getLastVisitsDetails not returning the full date range


I am attempting to use the API method Live.getLastVisitsDetails in order to save a CSV of a particular month. Setting the period to month and the date to a day in September only has a CSV with the last day of September as opposed to the full month. Similarly, I tried to set the period to range and gave a valid date range but only got the details for the last day in the range. I am not sure if there is something that I am missing.

Thank you!