Histograms of successful _pΔMSE fits with equal SU start vector and stochastically varied elements. For each of the 19 SU vectors (abscissa), at least five successful_pΔMSE fits were required to include them in the histogram. The fits with ΔMSE₁ = 0 were omitted. Reasonable numbers of successful_pΔMSE fits were obtained for all CHA^x models. The number of successful_pΔMSE fits was maximal near the SU vector of 10⁻¹ and drops to both larger and smaller SU vectors to zero. The number of successful_pΔMSE fits for all SU vectors decreases for the more complex models.