Measurements of Type Ia Supernovae (SNe Ia) in the near-infrared (NIR) have been used both as an alternate path to cosmology as opposed to optical measurements but also as a method of constraining key systematics for the larger optical studies. With the DEHVILS sample, one of the largest uniform NIR samples, we check three key systematics: the reduction in Hubble residual scatter as compared to the optical; the measurement of a ‘mass step’ or lack thereof and its implications; and the ability to distinguish between various dust models by analyzing correlations between Hubble residuals in the NIR and optical. We produce accurate simulations of the DEHVILS sample and find that, contrary to assumptions in the literature, it is harder to differentiate between various dust models than previously understood, and it is unclear how standard SNe Ia truly are in the NIR.