Does the -A parameter even do anything when -k0 is set? From the manual it sounded like the -A parameter was dependent on the -k parameter being >0?
-k controls the degree of black point hue correction. -A controls the blend rate between the fully corrected neutral axis and the possibly-not-fully-corrected black point. For -k 1, the -A parameter will do nothing because the black will be fully hue corrected, so the -A parameter is only relevant when -k < 1, and most relevant when -k == 0. This is all explained in the dispcal documentation. Graeme Gill.