My discussion on Atik and Sitar's paper was published in the ASCE JGGE August 2012 issue (Jonathan Pease, Discussion of Al Atik, L. and N. Sitar, 2010, Seismic Earth Pressures on Cantilever Retaining Structures, ASCE Journal of Geotechnical and Geoenvironmental Engineering). Much of the discussion and questions I included in the discussion are included under the Nay Sayers section.
Unfortunately, there is no response / closure by the authors in this issue that would answer my questions on their paper. I will post a copy of the discussion in the next day or two on the site. The only problem with a discussion on a very dense (generally good) paper is that its like reading a footnote discussion where you need the entire paper to understand what the issues are.