The new copyright maths

The MPAA's PR page on copyright points to http://www.copyrightkids.org/teachrentframes.htm, which is a "Parent-Teacher Resource Page" to provide:

"an educational tool to define, explain, and apply copyright issues in language understandable to Middle School students.
an educational resource on copyright issues for teachers and parents of 5th - 8th graders who are engaged in a creative process.
instructions about how to protect your own creations by registering them with the U.S. Copyright Office in the Library of Congress, Washington, D.C."

In their copyright basics page there is a section on term of copyright, which perhaps explains why there is so much confusion over the actual length of time a copyright lasts for:

"How Long Does Copyright Protection Last?

Copyrights do not last forever, but they do last a pretty long time. Under the current laws, copyright protection starts from the moment of creation of the work and continues until 70 years after the death of the author or artist. That means that if someone who is 15 in the year 2001 writes a story that year and dies when he is 85 in the year 2086, the copyright will not expire until 70 years after 2086 -- in the year 2156, which is 130 years away."

I had a wry grin at this. The PR folk don't appear to be able to count. A 15 year old writes a story and dies 85 years later at the age of 85 (lost a few birthdays along the way no doubt); it also seems that there are only 130 years between 2001 and 2156;and potentially,that 70+85=130 rather than 155 and 70+70=130 rather than 140. Copyright propaganda is not only creating a whole new reality, it's creating a whole new area of mathematics. Mind you, 2086+70=2156, so they do have the requisite partial contact with the real world.

Parents, teachers and children are supposed to take this seriously?