Unable to overwrite previously saved arguments

The order of operations in installer / maintenance tool produced by QTIFW is:

1. read custom arguments (as variables) from command line
2. read variables saved in .ini file
3. ...<do stuff>...
4. save all variables in memory to .ini file (including those custom arguments)

This creates a fatal issue that once a variable is saved in .ini file, it cannot be overwritten by argument passed into command line. It is not an issue in installer (it has no .ini file), but it is an issue in Mantenance Tool, because all custom arguments passed to installer during installation are saved into .ini file (with no way to unset them or invalidate their value). And when trying to use Maintenance Tool, they cannot be reused.