Sea of Tranquility

Well-written and easy-to-read story involving time travel and some light philosophy on the simulation hypothesis, but the plot seemed to have a lot of holes. For example (spoilers):
1. Why would the Time Institute send people to be in jail back in time if they are worried about them messing with the timeline? Even in jail, you can easily have influence on the world, and these people have no incentive not to interfere at that point.
2. How would the Time Institute even know it had been tampered with? To take an extreme example, if someone goes back in time and destroys the creator of the time machine itself, then no one in the future would be left to do anything about it. (A better handling of a similar setup is in Asimov's The End of Eternity).
3. It doesn't really make sense to me that a simulation would have trouble simulation the same person in two places. Presumably a simulation is done at the level of individual molecules/atoms, and not each human separately, but even if it is, there's no issue in computers with copying some particular program and running it simultaneously. For a better treatment of this idea, see Permutation City by Greg Egan.
4. Not exactly a plot hole, but the motivation for the main character to break the rule and save someone's life was not very clear. He just does it basically immediately, 5 min after swearing he won't. It would have made more sense for this to be better developed. Similarly, why did the main character go through with learning violin and fulfilling his fate? Based on his previous actions it seems like he might have wanted to resist it just to see what happens.

Overall, the book was easy and pleasant to read because of Mandel's fantastic writing style, but it didn't do well as a sci-fi novel, compared to others that tackle similar issues. I can see how it would be more appealing to a read that didn't have as much experience with science fiction.