CVT Fail Safe blah blah blah advice please

[Block215]

I own a 2010 Altima with the cvt of course. About 15 months or so ago, before last summer, I got my transmission flushed but with what I believe to be Castrol CVT fluid and not the NS-2. Ever since then every time I have driven on the highway around 75+ mph during hot days the car of course will go into fail safe mode.

I then had a transmission cooler installed. Didn't work. The warm weather is back and the transmission runs perfectly fine except during those hot days when I assume the non-Nissan transmission fluid gets too hot.

My question is if I get another transmission flush, 230,000 miles btw, and get the NS-2 fluid put back into my transmission would the car go back to riding normal during hot days on the highway? Is this an option or am I totally screwed?