One reason might be that there can be a few days of difference between the registration date and the appearance in the DNS; legacy data feeds and NRD use the latter date in the file names. Note also the possible time zone differences. Further, in the case of most country-code TLDs, it is impossible to legally determine a list of newly registered domains. In legacy / NRD 1.0 feeds, we only offer domain discovery which may or may not detect a new domain. NRD 2.0 offers a more sophisticated logic that gives partial lists of newly registered domains in more TLDs, but those lists are, in some cases, not necessarily complete either.