Nominatim planet update

Back in October I did a full planet install. I unfortunately did not enable updating and have started doing it now. My question is am I doing the update correctly?

These are the local.php settings I am using the default global minutely diffs. @define('CONST_Replication_MaxInterval', '40000'); @define('CONST_Replication_Update_Interval', '86400'); @define('CONST_Replication_Recheck_Interval', '900');

Every time I run the update I see something like Replication Delay is 6674939. The delay is getting smaller, but by random amounts. Is this supposed to happen? How many times will I have to run the update?