retain LAST snapshot of the hour/day/week/month, not FIRST

Hello,
having a cron job regularly backing up systems at 6 AM, when I edit files and configs on the said systems, I like to take a manual backup immediatly after.
Problem is, after the retain policy time is passed, btrbk will preserve the FIRST backup of the day, the one at 6AM, not the LATEST (the one I did), that is actually the most updated one.
Is it possible to add the option to change this behaviour so to keep the last snap of the period (hour/day/week...)?