  The dynamic coupling effects on fusion cross sections for reactions $^{32}$S
+ $^{94,96}$Zr and $^{40}$Ca + $^{94,96}$Zr are studied with the universal
fusion function formalism and an empirical coupled channel (ECC) model. An
examination of the reduced fusion functions shows that the total effect of
couplings to inelastic excitations and neutron transfer channels on fusion in
$^{32}$S + $^{94}$Zr ($^{40}$Ca + $^{94}$Zr) is almost the same as that in
$^{32}$S + $^{96}$Zr ($^{40}$Ca + $^{96}$Zr). The enhancements of the fusion
cross section at sub-barrier energies due to inelastic channel coupling and
neutron transfer channel coupling are evaluated separately by using the ECC
model. The results show that effect of couplings to inelastic excitations
channels in the reactions with $^{94}$Zr as target should be similar as that in
the reactions with $^{96}$Zr as target. This implies that the quadrupole
deformation parameters $\beta_2$ of $^{94}$Zr and $^{96}$Zr should be similar
to each other. However, $\beta_2$'s predicted from the finite-range droplet
model, which are used in the ECC model, are quite different. Experiments on
$^{48}$Ca + $^{94}$Zr or $^{36}$S + $^{94}$Zr are suggested to solve the
puzzling issue concerning $\beta_2$ for $^{94}$Zr.
