As always, I defer to Lori Sawaya in all things color. As should you. But I will add my 2c about SW matches of Ben Moore colors. They will struggle with many of the lighter colors, whites and near-whites, because the SW base is already darker than Ben Moore's BEFORE any tint is added. Thus, if you are trying to reproduce a very light color, you have that to contend with.
In particular, I have never seen SW match Simply White. I've had to go on several calls because of it. The SW version comes out looking more yellow-green than the Ben Moore color - no big surprise here because of the SW Extra White base. Extra White is at 113 degrees on the Lch color wheel (Green-Yellow hue family), with a lightness of 94.4. Remember, this is just the plain base.
Yet Ben Moore's Simply White color is only at 106.6 degrees (Yellow family) with a lightness of 95.6. You can't make a white base any whiter, and you can't overcome a yellow-green tinge except by adding a certain amount of pigment... which of course, would make the color darker.
It's possible SW could match Simply White in their High Reflective White base. I can't say definitively, because I've not seen it attempted. But mechanically, it ain't happening in their Extra White base.
Q
Why SW can't color match BM Simply White.
Q