Problem with archive.php

Archive.php is set to archive daily stats “at most every 1800 seconds” and weekly, monthly and yearly stats “at most every 6200 seconds”.
So, if I run archive.php every hour, I would expect that daily stats are processed every hour and weekly, monthly and yearly stats every two hours.
But I see that weekly, monthly and yearly stats are processed only if daily stats of previous hour were not processed. If they were processed Piwik says that existing weekly, monthly and yearly stats are less than 6200 seconds old.