Download report mismatch with bar graph?

My journal published an article which has (for us) a high file-download count, according to the public-facing bar graph on the website, over 2,000 downloads:

However, when I asked the journal site to issue a “custom report,” the Excel spreadsheet indicates that article has only had 1,347 article file downloads.

To generate the report, I chose “Statistics > Report Generator,” then scrolled down to the “Generate Custom Report” button, and on that page, under “Default report templates” I selected, Article file downloads. I unchecked all “Aggregate stats by” options, and selected a custom range to span all time that we’ve been in publication (we’ve only been a journal for a few years). In Advanced Options, under Columns, I selected only Article, and likewise in Filters I selected Article.

Did one of my selections result in this discrepancy?

Thanks for any advice!