All I know for sure is that it's a lower viscosity, but still compatible with NS-2. I'd assume it's a step above NS-2, but I can't say for certain how.
I think i will just use this i only need 5 qts. I would hate to use the castrol and have something happen even though i doubt it would have anything to do with a failure.
I've used the Castrol and Valvoline CVT fluid in a high mileage, now over 170K, ex-Hertz rental with excellent results.
I would use either with confidence. I am about to service the trans again soon.
Nissan also said their transmissions were worth anything. NS-3 in an NS-2 application is perfectly fine. Did it myself for many, many thousands of miles. I did it on the recommendation of a Nissan tech and never looked back.
Of interest, but no real importance, the 2013 Altima with the 3.5L/CVT (same powerplant as the Maxima) combo specs NS-3. Kinda weird.