LinuxQuestions.org - multiple concurrent dhcp leases for the same mac?

Ubuntu 10.04 LTS, dhcp3-server is installed via apt-get, nothing fancy in the config.

I have some scripts that parse out dhcpd.leases for quick easy monitoring, I noticed this.. There are 890 lease sections in the file, but only 551 unique mac's. At least the all mac/ip combinations are unique, but it's screwing up my reporting. Is this supposed to be happening? I see the "option agent.unknown-6" line is different in every entry.

Code:

lease 10.0.152.107 {

  starts 3 2011/11/09 14:34:13;

  ends 4 2011/11/10 14:34:13;

  cltt 3 2011/11/09 14:34:13;

  binding state active;

  next binding state free;

  hardware ethernet ac:81:12:11:02:7c;

  uid "\001\254\201\022\021\002|";

  option agent.unknown-6 "10977F1521FC6AC045FB61172E08D939@mydomain.com";

  option agent.remote-id ac:81:12:11:2:7c;

}

lease 10.0.152.107 {

  starts 3 2011/11/09 14:35:20;

  ends 4 2011/11/10 14:35:20;

  cltt 3 2011/11/09 14:35:20;

  binding state active;

  next binding state free;

  hardware ethernet ac:81:12:11:02:7c;

  uid "\001\254\201\022\021\002|";

  option agent.unknown-6 "65818B133529E07501AD28103E2D8ECC@mydomain.com";

  option agent.remote-id ac:81:12:11:2:7c;

}

lease 10.0.152.107 {

  starts 3 2011/11/09 14:35:49;

  ends 4 2011/11/10 14:35:49;

  cltt 3 2011/11/09 14:35:49;

  binding state active;

  next binding state free;

  hardware ethernet ac:81:12:11:02:7c;

  uid "\001\254\201\022\021\002|";

  option agent.unknown-6 "5013227A65F8C3485B126FA01DA17ADC@mydomain.com";

  option agent.remote-id ac:81:12:11:2:7c;

}

lease 10.0.152.107 {

  starts 3 2011/11/09 14:36:24;

  ends 4 2011/11/10 14:36:24;

  cltt 3 2011/11/09 14:36:24;

  binding state active;

  next binding state free;

  hardware ethernet ac:81:12:11:02:7c;

  uid "\001\254\201\022\021\002|";

  option agent.unknown-6 "4A9496D6181BA2B21E967FC711832047@mydomain.com";

  option agent.remote-id ac:81:12:11:2:7c;

}