For a design choice, specific paints for afv's into the SDW Shading Colors range - p.ex. ral 7028 dunkelgelb, olive drab, russian green - have a more intense / darker shade, instead of being arbitrarily reduced-to-scale.
Here why :
•first of all the model may require, or you might like, a more intense color shade
•second, it is easier to enhance the three-dimensionality with lights and shades (a technique that others call modulation ...) having intense tones available from the start
•third, in case of common error, for example excessive lightening of the high areas, it is easier to recover with a glaze of the base color (which is more sature) + Glossy Additive
•Fourth, given the numeber of scales in modelling, an "a priori" scale reduction of the paint is not satisfying.
In case of "normal" painting (without preshading / postshading), you can add to colors and mixtures TESC02 White or TESC16 naples yellow (the latter also contained in Paint Variation & Weathering Set TESE23).
It is valid also for the paint mixes suggested below.