The doom and gloom on internet forums is entertaining.
While I'm not a chemical engineer, I am a mechanical one and have designed various sealing widgets.
No seal is perfect, nor is chemical compatibility. I, too, run SUDT. But crikey, at the end of the day it's just a hydraulic circuit.
One product I worked on used Dextron III in a hydraulic circuit (with similar-ISH industrial pumps, compensators, motors, etc).
Dad runs Ford oil and has for 15+ years. I dislike the "i've been doing it for xxx" statements because they don't prove anything, but it goes to my point. It is NOT all doom and gloom. I've even <gasp> switched from dino to synthetic and back to dino in one of our cars. Oh the humanity!
Mostly I agree with the "cheap insurance" comments. That said, over the lifetime of a tractor thousands could probably be saved. That's another implement, or a few car payments, or whatever. Bottom line is that we can all "nickel and dime" ourselves into the poor house. We all choose to save in some places and splurge in others. I will *not* give you a hard time about buying off-brand oil. I doubt you'd ever notice, especially if it's mostly summer use. I use mine for blowing snow for 1/3 of the year, so I wanted synthetic. I like *all* types of synthetic oil. I even ran synthetic in my Boss plow, when I had it.
So on the forum where we all blab our opinions and argue it like facts.....that's mine.
Carry on!