If you want Kendall Charcoal but you're buying Dulux, go for Stormy Retreat. It lands at ΔE 1.7 from the original (LRV 13.3) — anything under 2.5 is a very close match, and at 1.7 you're well inside that. In real-world conditions, on a wall, with the inevitable variation in light and sheen, the two are practically indistinguishable.
Your backup is Wild Mushroom at ΔE 2.2 (LRV 13). Still a genuinely good match and within the "very close" band, but it shades a touch warmer and earthier than Stormy Retreat. If your room is north-facing and you want to keep that cool, slightly green-grey charcoal character that makes Kendall Charcoal so well-liked, Stormy Retreat holds it better.
Both sit at almost identical LRVs to each other — low teens — so you're getting the same depth of colour either way. That's the bit that matters most for a charcoal: get the lightness wrong and the whole feel changes. These two nail it.
The "but what about" here is finish. Benjamin Moore's sheens don't map one-to-one onto Dulux, and a charcoal will look noticeably different in matt versus eggshell — sheen pulls the depth around more than the pigment match does. So decide your finish first, then judge the colour in that finish, not off a flat sample card.
Practical advice: don't trust a printed swatch or a screen for a near-black like this. Get a Dulux sample of Stormy Retreat, paint two coats on a bit of lining paper, and move it around the room over a day. North light, lamplight, and full sun will each tell you something different. If it reads slightly cold and you'd prefer a hair more warmth, switch to Wild Mushroom — that's exactly the trade-off between the two.