Exponential data consistency conditions (eDCCs) are equations that express the redundancy of information between exponential projections. Exponential projections can be derived from parallel SPECT projections and be used to detect and correct for patient motion during the acquisition. However, other physical effects such as collimator resolution, scatter or noise could also introduce inconsistencies in the projections. The purpose of this work was to evaluate the impact of these effects on the eDCCs. We used ray-tracing and Monte Carlo simulations to generate different sets of projections and compared their consistency with two metrics based on eDCCs: the absolute relative difference and a noise-aware metric that takes into account the acquisition noise. The collimator resolution, the scatter and the movement increase significantly the error in the eDCCs. The noise-aware metric was more sensitive to patient motion than other effects.