  We rederive the new SU(3) multiplet mass formula
2M^2(s\bar{s})+3M^2(n\bar{n}, I=1)=4M^2(s\bar{n})+M^2(n\bar{n},I=0) (n=u,d},
obtained in our previous paper by using Regge phenomenology, for the
pseudoscalar and scalar mesons in the Nambu-Jona-Lasinio model with
instanton-induced interaction. We apply this formula to the problem of the
correct q\bar{q} assignment for the scalar meson nonet. Our results strongly
favor the masses of the scalar isoscalar mostly octet and mostly singlet states
in the vicinity of 1.45 GeV and 1.1 GeV, respectively
