The idea is to identify if there is a particularly easy/hard exam and the average score of the cohort is significantly different to how they perform in other classes. "Doing poorly" is quite hard to define when none of the tests, perhaps outside of the core 1st and 2nd year modules, are standard.
Not really since then all students can learn the exam as a template after 2-3 exams leak.
The curving I know at uni was targeting to exmatriculate 45% by the 3rd semester and another 40% of that by the end so the grades were adjusted to where X% would fail each exam. Then your target wasn't understanding the material but being better than half of the students taking it. The problems were complicated and time was severely limited so it wasn't like you could really have a perfect score. Literally 1-2 people would get a perfect score in an exam taken by 1000 people with many exams not having a perfect score.
I was one of the exmatriculated and moving to more standard tests made things much easier since you can learn templates with no real understanding. For example an exam with 5 tasks would have a pool of 10 possible tasks, each with 3-4 variations and after a while the possibilities for variation would become clear so you could make a good guess on what this semesters slight difference will likely be.
