Eddie,
Messick's posted a U Tube video recently in which they disected Kubota, NAPA, Wix, filters, Wow, there was a significant difference, no trick photography!!!
In gear tractors, most PREMIUM HYD fluid is acceptable. In a hydro, I stay w/ mfg name brand, My MX hyd oil Service was almost $300 just for hyd SUDT. Excluding filters.
I use diesel synthetic crankcase oil as well but not kubota brand, yet ALL FILTERS are kubota.