  We discuss some physical prospective of the non-BPS effective actions of type
IIA and IIB superstring theories. By dealing with the complete all three and
four point functions, including a closed string Ramond-Ramond (in terms of both
its field strength and its potential), gauge (scalar) fields as well as a real
tachyon and under symmetry structures, we find various restricted world volume
and bulk Bianchi identities. The complete forms of the non-BPS scattering
amplitudes including their Chan-Paton factors are elaborated. All the
singularity structures of the non-BPS amplitudes, their all orders $\alpha'$
higher derivative corrections, their contact terms and various modified Bianchi
identities are derived. Finally we show that scattering amplitudes computed in
different super-ghost pictures are compatible when suitable Bianchi identities
are imposed on the Ramond-Ramond fields. Moreover, we argue that the higher
derivative expansion in powers of the momenta of the tachyon is universal.
