Zero average values of cosmological perturbations as an indispensable
  condition for the theory and simulations
  We point out a weak side of the commonly used determination of scalar
cosmological perturbations lying in the fact that their average values can be
nonzero for some matter distributions. It is shown that introduction of the
finite-range gravitational potential instead of the infinite-range one resolves
this problem. The concrete illustrative density profile is investigated in
detail in this connection.
