I was wondering what is the difference between using pkt.time and pkt[IP].time since they both give different times for the same packet.
I was also wondering how to interpret packet time such as 1430123453.564733 
If anyone has an idea or knows where I can find such information it would be very helpful.
Thanks.
pkt.time gives you the epoch time that is included in the FRAME layer of the packet in wireshark. 
Just after the notation pkt[IP].time gives you the time that is included in the IP layer of the packet in wireshark. But the IP layer has no time, so I don't think this command will work.
Scapy packet time interpretation