When estimating phase aberrations due to volume turbulence, a discreet set of estimate phase screens are located axially between a known, aberrated pupil field and the object plane. The pupil field can then be back-propagated to the object plane through the estimate phase screens to correct for the turbulence. To improve processing time, sharpening software is restricted to a limited number of phase screens, which results in estimate phase screens correcting for turbulence from different axial locations. We have investigated the performance of our Sharpness Metric Maximization (SMM) routine as a single, spatially bandlimited, estimate phase screen is displaced axially from turbulence restricted to a single plane. This gives insight on how best to construct a phase estimate scheme to maximize performance and computational efficiency.