  The advanced ENZ-theory of diffraction integrals, as published recently in J.
Europ. Opt. Soc. Rap. Public. 8, 13044 (2013), presents the diffraction
integrals per Zernike term in the form of doubly infinite series. These double
series involve, aside from an overall azimuthal factor, the products of Jinc
functions for the radial dependence and structural quantities $c_t$ that depend
on the optical parameters of the optical system (such as NA and refractive
indices) and the defocus value. The products in the double series have
coefficients that are related to Clebsch-Gordan coefficients and that depend on
the order of the Jinc function and the index $t$ of the structural quantity, as
well as on the azimuthal order and degree of the involved Zernike term. In
addition, the structural quantities themselves are also given in the form of
doubly infinite series. In this paper, we give truncation rules for the various
infinite series depending on specified required accuracy.
