1. It is very logical. Nolan creates an alternative universe where he explains the logic, and then creates a fantastical movie using this logic to present accurate sequences where a forward -moving person fights with his inverted self, or the car scene at Tallinnn - or even the extremely important double-shot building. Even if events are immutable, the logic he employs creates a singular timeline with a single temporal anomaly he hides in the editing.
2. At the same time, its only pseudo science. Although he bandies about theoretically accessible concepts, and even references Feynman's idea of a singular positron existing everywhere at once and moving backwards, and has Maxwell's Demon illusrated on the white board (an attempt to separate "stages" of entropy which seems to work until you consider the "work" the demon expends). Entropy can approach zero, but never touches it. Of course, we don't know what we don't know; maybe Nolan's notion beomes a discovery in 100 years...
3. You stumbled on the watch paradox, but it only happens when a pair are crossing each other in opposition, but then one invert/reverts.that the dime discrepancies (anomalies) happens. Let me try to explain.

Think of a timeline going forward. You and I both invert a minute aopart. -You go first at 12:00. I go at 12:01. My watch (not a countdown watch) starts going backwards from 12:01, and when it hits about -12:00, you appear with your watches in synch, but counting down.

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Can you picture that? Its why a whole -army is able to catch up with thermselves - the last oneto invert is the first one to appear in reversee entropy. If you imgine thi wutth dozens of people, you can see how a army goes through if they had normal watched (if you watch the watch hands rather than the digital display, inverted watches defiitelytell time from now into the past) and wind up in sync once the first person to invert beomces the last to join the group.

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This holds true of any pair/group that travels together

HOWEVER -= the big caveas to not invert once you have crossed the midpoint of the "countdown." . Here's how it creates an anamol, and is what you were thinking...

If two characters are crossing temporal paths, if the inverted character reverts before teh midpoint, he is still "in the future." He will suddenly appear out of a turnstile, in what is effectively the same as the last part half of two people inverting/reverting where they are in opposition (like at }

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