This is a bit of a problem, as it's difficult to distinguish an IP change from a host using several IPs (e.g. when the router has new and old entry in the ARP cache). I've added new retire values in the latest NeDi versions. 1 for links (as obsolete ones shouldn't stay 30 days either) and 1 for ARP values.
From your IPchanges I see, that they change quite frequently indeed and this is a printer, right?