  A method for computing singular or nearly singular integrals on closed
surfaces was presented by J. T. Beale, W. Ying, and J. R. Wilson [Comm. Comput.
Phys. 20 (2016), 733--753, arXiv:1508.00265] and applied to single and double
layer potentials for harmonic functions. It uses regularized kernels, a
straightforward quadrature rule, and corrections added for smoothing and
discretization errors. In this note we give estimates for the discretization
corrections which show that they can reasonably be neglected with proper choice
of numerical parameters.
