The reason is the maximum number of rows in the print report — 40 (the first 20 and the last 20). In XML format, all rows are always included, so the import to the portal is correct.
From it, you can then obtain a complete print output of the summary report.
However, there is an add-on available that ignores this limit and generates all rows included in the summary report. It is available for free download on our website.