If there is a sub-dial at the top and one on the bottom for the time elapsed, such a 'complication' could make sense for him.
Karl Barth, this wise theologian and radical democratic socialist (called 'comrade of God' by scoffers and his friends alike), who gave his good advice to everyone and explained to us what's right or wrong, lived with two women at the same time under one roof. There was his wife Nelly (with whom he had 5 children) and the mistress Charlotte (called 'Lollo').
Maybe he stopped the time spent with Nelly and Lollo to give each of them their fraternal share.
Oh … and they were all buried in the same grave. That's what I call consistent.
@OP: Sorry, this doesn't help you to find the model and make of his watch, which I am afraid won't be possible without better images. I was just immediately reminded that we were dealing with this moralizer in school (highly controversial - teacher (she) against the class).