DP4+ is a popular tool for structural elucidation using GIAO NMR calculations. The method was built with 16 statistical parameters [μ,σ,ν], which depend on the level of theory. Herein, we deeply analyzed the sensitivity of DP4+ when using improper [μ,σ,ν] sets, a common situation found in the literature. The results led us to develop a customizable DP4+ methodology that allows preliminary calculations at any desired level of theory using a small set of training molecules.