If I'm correct in my checking, all the places in the "America/Sao_Paulo" zone have had the same wall clock time since 1970 (the UNIX epoch).
We normally wouldn't normally create separate zones in this situation.

                               --ado

From: Guilherme Rodrigues [mailto:oguilherme@gmail.com]
Sent: Monday, January 04, 2010 2:18
To: tz@lecserver.nci.nih.gov
Subject: little nuance in brazil 1963

Hi,
    I notice a little nuance that would be nice be corrected, between 1963-10-23 and 1963-12-9 in brazil only Minas Gerais , Espirito Santo, Rio de Janeiro and Sao Paulo had sumer time. this can be verified in the links.
http://pcdsh01.on.br/DecHV.html
http://pcdsh01.on.br/HV52700.htm
http://pcdsh01.on.br/HV53071.htm
   
    I propose separate Zone America/Sao_Paulo in one more zone America/Brasilia, the configuration would be like:
# Minas Gerais (MG), Espirito Santo (ES),
# Rio de Janeiro (RJ), Sao Paulo (SP)
Zone America/Sao_Paulo -3:06:28 - LMT 1914
   -3:00 Brazil BR%sT 1963 Oct 23 00:00
   -3:00 1:00 BRST 1964
   -3:00 Brazil BR%sT
# Goias (GO), Distrito Federal (DF),  Parana (PR),
# Santa Catarina (SC), Rio Grande do Sul (RS)
Zone America/Brasilia -3:06:28 - LMT 1914
   -3:00 Brazil BR%sT 1963 Dec 9 00:00
   -3:00 1:00 BRST 1964
   -3:00 Brazil BR%sT               
           
Ps.:Sorry my poor english