Just a note in all this. I use the same stuff that I use in the Cummins ISX in my semi. By far the best coolant out there is the newer ELC (red) that you can get at truck stops and truck dealers. It is an OAT type formulation that is specifically designed to eliminate cylinder liner cavitation and it requires no SCA additives. Price isn't bad compared to other stuff. It is a long life coolant.
Depends on the model year your Cummins ISX was built. Up until about a year and a half back, no ISX could operate with the OAT coolant from Shell, Chevron (Texaco) or use CAT ELC OAT. The issue was the organic acid inhibitor used in these coolants, 2-ethyl hexanoic acid. It has a proven track record on attacking silicon rubber elastomers such as found in ISX engine coolant gaskets and silicon rubber coolant hose liner. After the change in 2008, I can research the engine serial number, Cummins changed from using silicon rubber to an elastomer called HNBR, a top level fluoro elastomer. It is not damaged by that OAT acid.
When you say it needs no SCA additives, you better read your OAT coolant literature closer. If you can keep it in the cooling system, it will require the use of an extender liquid at 300,000 miles. I say "IF" because typical on-highway trucks leak the entire volume of the cooling system (12 gallons on an ISX) in about 16 months. You will be replacing this coolant on an ongoing basis. Keep that in mind when thinking of it as a "long life" coolant. You will not achieve long life because of leakage issues. It is not just OAT coolants but all coolants that have this issue in typical on-highway trucks.
It is not any more specifically formulated to prevent/reduce liner cavitation pitting than any other coolant that meets ASTM D6210. It is just another choice.
Also, the above listed OAT coolant manufacturers say you do not need to test your coolant SCA level. That would be true if you never refill low coolant levels with any coolant that does not contain a healthy dose of SCA. OAT coolants claim they do not have SCA but they do, they just prefer to call it something else. If you use a test strip like Fleetguard CC2602, you will find your OAT coolant has nitrite and molybdate. If your OAT coolant is a product called Final Charge, then you will not find anything with the test strips. Then you need to be concerned that another similar looking coolant like DEXCOOL could be used to top off low coolant levels. Final Charge can protect against cavitation pitting, DEXCOOL is worthless at that task. Better to test and know that you have protection (providing you are using Shell Rotella ELC, Chevron Delo ELC or CAT ELC.
Under the right operating and equipment conditions, OAT coolants do well. They do not do well when any and everybody is refilling the coolant level. Too much opportunity to refill with the wrong coolant but of similar color. The above listed OAT coolants (except Final Charge) should never be used in a system that has lead solder as it is well capable of attacking solder and causing leaks. Neither are these coolant particularly good in high coolant flow systems in protecting aluminum surfaces. This becomes even more critical when the coolant is diluted with too much water. High water content coolants and aluminum surfaces are not a good match at all.
The idea that OAT coolants need the organic acid technology to achieve long coolant life is not a technical fact but is a statement from aggressive marketing and sales groups bent on creating a market for what is "just another coolant product choice".