Ok, I screwed around with the splitter again today and I found out why the detent would not kick off on the return cycle................
It was "built" that way by the dealer...........
After setting pressure relief valve to my satisfaction (and my tractor's satisfaction), and setting the detent valve pressure to the minimum required to "set" the detent........... I got the same result I have been getting, IE it would not come out of detent at the end of the return stroke.
For shytes and giggles, I reversed the hoses at the quick disconnect and let the cylinder cycle. IE The valve set in detent on the "split" stroke (yeah, bass ackwards)........ At the end of the stroke............yeah you guessed it, the detent kicked out!
Turns out the short hose on the valve was plumbed wrong. Switched its location with the return hose on the cylinder and viola! it all works as designed.
That is what I get for buying the splitter from a meatball. I am delighted!
Thanks J.J. for your help. Your explanations of the two valve adjustments got my thinking cap going and pushed me into finding the problem.