OK --- I'll try:

First... "Been There - Done That ..."

Most -- if not all modern color negative materials have a built-in color bias... That is why there is a definite "orange cast" (actually, dark yellow) to the negatives when they are held up to the light. This bias eliminates (remember we have to think through the negative - positive frame) the need for a LOT of cyan filtration - in most cases - all of it - in printing.

If the ambient light in exposure deviates enough from that expected... say a 3600K projection lamp used with 5500K "Daylight" film, the - compliment of cyan - yellow bias will NOT be enough (remember: negative) to eliminate the need for all cyan filtration in printing. There will be a need for more than can be handled by the "bias".

I've read this a number of times. Terribly "choppy" but it makes sense to me.

In practice ... I start as usual - using a ColorStar 3000. From the image of a gray card, I'll modify the magenta and yellow filtration - until I run out of room ...I'll be at 00 filtration and still not achieve balance. Next, I'll add 30cc (or so) of cyan, and start all over.
So far, I haven't failed to "balance out" a negative.

BTW - this is just one reason I do my own color printing.