My first guess would be you have the Networker clone setting "Limit number of save set clones" set to zero.  You're probably cloning all savesets every time it runs.  You only want it to clone new savesets which would be 1.  You can confirm if this is happening by running mminfo -q"volume=[clone volume]" -r "ssid, cloneid" or something similar.  If you have multiple cloneid's for each ssid thats probably what is happening.

What does mainly mean?  Replication will always filter more than original backup does so it is expected to see more.  As to how much more, that is dependent on too many things.