This presentation concerns the development of yet another benchmark in a series for solution of the linear neutron transport equation, but using the Double PN (DPN) approximation. As more and more numerical and analytical solutions to the linear particle transport equation appear, their verification becomes increasingly important. There are numerous ways of solving the one-dimensional monoenergetic neutron transport equation in plane geometry, where PN and DPN methods play a prominent role. Here, a new method of solution, based on matrix algebra and scaling to avoid overflows and leading to a response matrix solution, is derived and demonstrated for a highly anisotropically scattering medium with a beam source impinging on a scattering and absorbing slab medium.