Sorry things are real busy workwise right now, tis the season for boating and breaking down. Regarding the use of OAT antifreeze, when it first came out there was a lot of chatter about trucks with Red Metal Radiators springing leaks soon after changing and it was primarily the solder that was leaking. Of course one can temper this with the thought that no doubt those rads had a lot of miles on them and their tiredness may very well of been part of the issue. However the OAT's do show to be more corrosive particularly to solder and yes it is below an acceptable spec. but acceptable specs are still somewhat arbitrary in nature. I also feel that heat exchangers are not lasting as long as they used too and whilst not a scientific observation, from my perspective being used to Green and just adding additive it was a no brainer to stick with it.
You have gone with a hybrid a mix of Inorganic and Organic which fares better with the corrosiveness and is what I recommend when the client insists on going high mileage. I wonder how much the Hybrid is reaction to early experiences with straight Organic Acid.
Cheers
Nobby