That 5% is room for improvement and your daughter can write an even better essay next time. If all 'great' essays get 100% then that leaves no room for rating each one against each other. To expect teachers to exclaim 'yes, that's it, it's the ultimate essay ever, 100% A++++++' ? it's like that bit in the Christmas Story. It doesn't need to happen.
Even if the teacher can't think of a single thing the student could have improved?
Maybe the last 5% is reserved for essays that make her weep at their greatness. In seriousness, though, I think 95%, the top grade in the class, is an excellent grade for an excellent essay. If the next essay provides even more depth of insight, making it measurably more excellent than the previous 95% standard of excellency, it could get 97%, and so on. Otherwise, how do you rank things against each other if everything acceptably good gets 100%?
^This. I agree with eee. Firstly the teacher didn't say she refuses to give over 95% for something. It's not a cap. She just said that she hasn't yet ever seen a paper worthy of higher than 95%. 95% is exceptionally good. It's world class but like eee said, a lot of teachers reserve the 100% for complete
Achillean masterpieces, something that would make 'one weep', the kind of essays that make you think endlessly into the night, change the world, reserved for the Oscar Wildes and Hemmingways of this world etc.. etc... Things like literature and history and philosophy essays are subjective. You can't always pinpoint exact loss of marks because that's not how feelings or soul works or how the written word flows. The same essay marked by two different teachers is unlikely to generate the same exact mark - but it's most likely to be in the same ballpark. A good essay is a good essay. One teacher might give it a 95%, another teacher might give it 91%. Both marks show that the essay is exceptional. The difference in marks cannot be pinpointed or explained because it's subjective. It's not something like Mathematics or Chemistry.
Your daughter can ask how she could do even better/how she can improve.. but to question the (already excellent) mark the teacher gave, in this case, the highest she has ever given out, I can't see as being anything but a bad idea.