MORE is not always
Many things in the world of chemistry act in such a way that more is definitely not better. Think of adding something as simple as sugar to a drink. Some adds flavor. More can make for a very unpleasant experience.
For example, sulfur compounds are used to protect your engine at lower engine temperatures. Phosphorus takes over at the much higher temps, and the sulfur cokes out forming sludge at those temperatures. More of either will not help your engine or the additives themselves and has, in fact, done actual harm.
So why add what’s already standard to your engine oil with one of these engine oil additives?