> I've a project, in the setup.py file, I've a function called update_prefix, that updates the
> 'path_project' variable with prefix arguments from setup.py
> If you runs setup.py with --prefix=/usr, then the file in 'projectname/projectnameconfig.py' is
> modified changing the 'path_project' variable from @PREFIX@+"share/projectname" to
> '/usr/share/projectname'. If you runs setup.py without prefix arguments, the prefix is '/usr/local'.

Did you write a custom 'install' class or are you for example looking at sys.argv to decide whether to run your function?  If it’s not implemented as a distutils command, it’s not surprising that it does not integrate well.

> [...]
> That is cause of the issue, that I explain in the early comment, I fixed it rounding to two decimals
> instead of rounding to integer.

Okay.  Can you make sure that this is the source of the problem, for example by adding time.sleep(1) between build and install?