Basicly Delo and Rotella are long haul deisel oils. These oils are designed for use in transport trucks running from one side of the country to the other. These vehicles run continusally, stopping only for fuel, driver change or a break down. At a preset time the oils are analysed for their lubricity, chemical content, composition and conatamination amongst other things. When these levels exceed a preset level, the oil is changed. To get the business the oil companies produce an oil that can handle this style of extreme use, thus reducing the amount of oil changes, reducing the long haul cost.
As the transport industry is driving the oil technology development, it is reducing the cost of oil, and improving the quality and the propertie of the oils. This has a follow on benifit for people who use these products, it gives us a high quality product that is cheap.
As far as the additives it does and does not run, they are hard to find info as that is the oil companies $$$$$$ maker, one thing is though, whatever they are they are designed to improve the life of the oil in one of the hardest enviroments around for oil.
As i said earlier, there is a great thread on here else where with all of this in it.