  The prediction of single particle level crossing phenomenon between
$2p_{3/2}$ and $1f_{5/2}$ orbitals in $Ni$- and $Cu$-isotopic chains by the
finite range simple effective interaction without requiring the tensor part is
discussed. In this case the experimentally observed crossing could be studied
as a function of nuclear matter incompressibility, $K(\rho_0)$. The estimated
crossing for the neutron number $N$=46 could be reproduced by the equation of
state corresponding to $K(\rho_0)$=240 MeV. However, the observed proton gaps
between the $1h_{11/2}$ and $1g_{7/2}$ shells in $Sn$ and $Sb$ isotopic chain,
and the neutron gaps between the $1i_{13/2}$ and $1h_{9/2}$ shells in $N$=82
isotones, as well as the shell closure properties at $N$=28 require explicit
consideration of a tensor part as the central contribution is not enough to
initiate the required level splittings.
