I do quite a lot of color palettes for my clients and this is my way of thinking: if the soffit is large and low, paint it the wall color. If its higher, paint it the ceiling color. For your ceilings: Take your wall color and mix it ceiling 20-40% lighter than the wall color (it will still be light but not such a stark white.) Ceilings = the 5th wall.

Thanks....this is very helpful. Our soffit is low and large, so we will go with the wall color. Also love the ceiling direction. It goes against 'conventional wisdom' to paint the ceiling white, but is so much softer and subtler.