You are correct that standard green ethylene glycol is what Kubota recommends, and is fine.
That said, one reason to use an extended life coolant is that you won't need to change it every two years. I switched all of my Kubota machines over to Zerex G05 years ago for the 5 year interval. There are plenty of other suitable coolants, but as JG4660 mentions DexCool is NOT one of them. Engines and cooling systems must be specifically designed for DexCool (and Ford's from 2011 on).
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