Similar tables, different indexes performance

Hi,

I know that it's not very polite thing re-send a question, but I don't
have any idea about why can this be happening. I have two almost
identical tables, with equivalent indexes, but their performances are
very different. In this case, I'm sending the queries, explains,
tables'structures and record counts. I think this is the place where I
can most probably get help about performance issues.

Thanks in advance,

--
+---------------------------------------------------+
| Alvaro Nunes Melo Atua Sistemas de Informacao |
| al_nunes(at)atua(dot)com(dot)br www.atua.com.br |
| UIN - 42722678 (54) 327-1044 |
+---------------------------------------------------+