I’m not sure I’m accurately visualizing exactly what you’re describing, but I know from experience working with a two-color offset press that the results are quite different if you print two colors in two passes vs one pass (in which the inks are combined on a “blanket” where they effectively mix together before being transferred to the paper all at once).

In the first case, the result is exactly what you’d expect from a subtractive color model; but in the latter case, the mixed ink that ends up on the paper is no darker than the component inks. The hue is similar whether overprinted or mixed, but the saturation is reduced in the mixed example.