For original article see Kaivani, et al., ibid, vol. 5, pp. 393-404 (2011). Lang and Nannarelli comment on the paper of Kaivani, et al., which reported a proposed unit ~46% faster than the unit from their study. Lang and Nannarelli show in this comment that the evaluation done by Kaivani, et al. is based on wrong assumptions and the results of the comparison are erroneous.