My skintone is mainly cool yellow + gray, so muted yellow. Most neutral foundations are obviously too warm + saturated/pink, and cool foundations tend to look cool enough but are just too saturated/pink. Most warm foundations will also pull too warm/saturated, and when I find one that is cool yellow enough it is not muted so the right color but too saturated.

If you get very technical I do have yellow and blue undertones, which could be classified as olive. I think the differences is that green is very difficult to detect in my skin. Most olive foundations will be the right amount of muted yellow but pull too obviously green on me. So I need blue mixed with yellow to cool it down, but not enough to make it appear obviously green.