  Theory of strong decays defines in addition to decay widths, also the channel
coupling and the mass shifts of the levels above the decay thresholds. In the
standard decay models of the 3P0 type the decay vertex is taken to be a
phenomenological constant "gamma" and such a choice leads to large mass shifts
of all meson levels due to real and virtual decays, the latter giving a
divergent contribution. Here we show that taking the microscopic details of
decay vertex into account, one obtains new string width coefficient, which
strongly suppresses virtual decay contribution. In addition for a realistic
space structure of the decay vertex of highly excited states, the decay matrix
elements appear to be strongly different from those, where the constant "gamma"
is used. From our analysis also follows that so-called flattening potential can
imitate the effects of intermediate decay channels.
