Rodolfo,
Thank you
Very Much!!
I had looked at only a few these Tarifa files on-line, and those I looked at were not changed. My carelessness.
With your two links as a start, I went back to the Correos de Mexico website, and looked at all of the posted Tarifa Files. From what I observed, it appears that only the five rate files for International mail were updated (the two you identified, and three others).
Is it your understanding that only the International rates have changed at this time?
I next looked at the second part of the Tarifas - for "Masivos", which I think of as Bulk Mail. The only Tarifa I found here with the new date was list 9) Sacas Especiales M, or "M-Bag" mail.
Also in this section, no file was present for entry

in the list Cartas Internacionales. (I got a download error - file not found)
I also notices a few subtle changes in the organization of these pages.
Several of the current Domestic Rate files which had been posted on-line gave an effective date of 24 Feb 2010. Other sections of the previously posted Tarifa had no date associated with them. Can I interpret this to indicate that this is the first rate change since 24 Feb 2010, or have there been other - possibly minor - rate changes that have occurred since?
Thanks for any additional information you might have.Mike