It is confusing and controversial, but Carl Calleman's interpretation makes the most sense to me,

[link to www.calleman.com]

clip: The second reason that we may understand the December 21, 2012 date to be wrong is that it falls on the tzolkin day 4 Ahau, since this is not a completion energy. It must fall on a date that is 13 Ahau, since this is the tzolkin energy towards which all the tzolkin energies are moving. This may be a more difficult argument to grasp than that the beginning of the traditional Long Count is based on a local tradition. To realize that the actual enddate must fall on an energy that is a 13 Ahau date essentially requires of someone that he or she for a relatively long time have followed exclusively the true tzolkin count. Only in that way would one be able to personally experience the energy shifts, and unfortunately not so many people do that. If people mix two different counts that we may be certain that there is too much confusion for the actual energy shifts to be felt. Yet, it is important to know that Don Alejandro speaks about a prophecy of the return of 13 Ahau that seems to have survived through the ages. Carlos Cedillo also alerted me to a passage in the Book of Chilam Balam of Chumayel that describes the energy of 13 Ahau as follows: "Holy completion of time, truly" - a statement not found regarding any other tzolkin energy in these prophetic Mayan books written a few hundred years ago. From a knowledge of the tzolkin it simply seems logical that the true Mayan calendar should end on a day that has the energy of 13 Ahau.

The placement of the enddate of this creation at the particular 13 Ahau energy of October 28, 2011 is supported by what seems to be a correction made in Palenque to the original Izapan Long Count several hundred years later. Most likely the priests of Palenque, who obviously meticulously followed the true tzolkin count then started to feel that there was something wrong with the correlation between the Izapan Long Count and the tzolkin.

[link to www.calleman.com]

[link to www.calleman.com]

Now with all the Elenin prophecies around October 26, I am more convinced than ever that Oct. 28, 2011 is the correct date.