I think if the OP would quit pouring that Smitty's stuff, which is clearly of unknown parentage, and would flush the hydraulic system with known, high quality oil, the problems might start to go away.
Even the Super-Tech oil from Wally World, I have some confidence in. If it doesn't meet spec, they have deep pockets and lots of lawyers would happy to take them on. Smitty, on the other hand, has to be found before he can be sued and then he has to have two nickels to rub together, which I very much doubt.
One thing that would help a lot is what does the oil look like that comes out of the machine? If it is cloudy, you probably poured anti-freeze in there. If it has been clear every time, then whatever you put in mixes with oil and it is just a matter of enough flushing. If it was cloudy the first few times, and is starting to become clear, you are on the right path, just need some more flushes.
My own opinion is that 25 gallons is not enough to flush a system that holds 10 gallons, really only two flushes. OTOH, 25 gallons of Smitty's has no legitimate use other than going directly to the oil recycling sump.