Thanks for your answer!
The list I have is from the back label, and since the brand is now owned by P&G, I’m confident it’s accurate. Although the INCI list on their website matches what you mentioned, I believe that one is simply incorrect.
Even putting the list aside, I’ve tried dissolving SCI with lower amounts of CAPB and SLS, but it hasn’t worked for me. I end up with a white, lotion-like consistency with clumps—nothing like the clear liquid in the original product.
You’re right that CAPB contains salt, but I’m not sure whether that salt is typically listed as a separate ingredient. Since sodium chloride is explicitly listed in their ingredients, they must have added extra salt in the formulation.