Mark Andy quality control

Hello! I'd highly appreciate some advices on how to adjust printing quality but using only D19C densitometer as afterprint measurement. Inks and materials I'll post in this if that requires, so far i only came across some formula looking like (D1+2 - D1)/D2;
Where D1+2 is density of the last layer color (for those consisted of 2 layers of ink)
And D1 and D2 are densities of each color respectivly. Can't quite figure out what is what