Who can help me, I want know why, Is it possible to modify this address?
Why? Because not very many games had RAM - it would have made the cartridge more expensive - but the mapper hardware still supported RAM. So it was easy to reuse that space that would have been used by RAM to instead hold a few bits of "outer bank" instead.
Can you change it? Depends on what you mean. The existing mappers are defined by the existing hardware, and you mayn't redefine a them to mean something that doesn't exist. On the other hand, one can modify ("mapper hack") an existing ROM to run on some other mapper that might do what you want instead.