This letter to the editor notes the offsets from the origin of unique hue loci in the recent article, Unique Hue Data for Colour Appearance Models. Part III: Comparison with NCS Unique Hues by Xiao et al. [Color Res Appl 2015;40:256-263] and suggests that modifications to the cone response function in CIECAM02 be explored. (c) 2015 Wiley Periodicals, Inc. Col Res Appl, 2015