Actions.getPageUrls numbers differ with the period I select

basically I’m issuing api requests like this ?module=API&method=Actions.getPageUrls&expanded=1&flat=1&date=2014-01-01,2021-12-31&period=year&idSite=4&token_auth=TOKEN&showColumns=label,url,nb_visits,nb_hits&format=JSON&filter_pattern=xyz%2F1-234&filter_column=url". The pattern is sort of “url prefix”, I’m trying to get everything under that prefix.
For this particular pattern if the period is year, I’m only seeing year 2018 in the results. If I change the period to month, I’m seeing results also in other years (for example 2017-11 or 2021-03), if I change it even further to weeks or days; I’m getting even more results.

I’m guessing this is due to datatable_archiving_maximum_rows_subtable_actions = 100, where only in 2018 the pages I’m interested in made it to the top 100. In the other years they fall into the “other” bucket and the filter can’t find them.

I wanted to check this reasoning is sound and this is really what’s supposed to be happening.