The “retrograph” function measures the number of times on the original watch that the retrograde 30 second feature resets (info thanks to @G1NT0N1C) - on my face it is not operational… I programmed that hand as 'Day of Month" (UL needed for “Day of Month” feature)
Exactly such problems arouse my interest: Nobody has solved them before and it is REALLY difficult. This is the kind of challenge that doesn’t let me sleep until I have solved the problem.