He doesn't go to bed before midnight. -- Il ne se couche pas avant minuit.
He doesn't ever go to to bed before midnight. -- Il ne se couche jamais avant minuit.

I think you're trying to read too much into the English. The simple English sentence "He doesn't go to bed before midnight" has a straightforward French translation. If you want to say that he NEVER goes to bed before midnight, that would change the way you say it in French.

What I'm saying is that this is a poorly-designed quiz question. We're given this sentence:

Il ne se couche pas avant minuit

And we need to choose between these two translations:

He doesn't go to bed before midnight

He doesn't ever go to bed before midnight

Those two English translations mean the same thing. 

As I said, I chose the correct answer — the sentence without the added word "ever." But we aren't being taught to translate word-for-word, because it's bad practice to use literal translations. We're taught to translate for meaning. So the quiz should give answer choices that differ in meaning.

If the given French sentence were:

Il ne se couche jamais avant minuit 

And the possible translations were:

He doesn't go to bed before midnight

He never goes to bed before midnight

Then I would be reading the French word "jamais" before translating. Although the English translations are similar, they don't mean the same thing. It's very clear which translation is correct because the French word "jamais" narrows the intended meaning. (In addition, there's a huge difference between "never" and the "doesn't ever" from the first question. "Never" is used for emphasis, and emphasis affects meaning.)

Basically, the quiz makers applied the same logic to two unrelated quiz questions where the same logic can't be applied. In the question that includes "jamais" you're teaching the construction "ne...jamais" — then the quiz question they designed was a good way to test if students know what "jamais" means.

But if you're teaching what it means to say "Il ne se couche pas avant minuit", you could translate that as either "he doesn't" or "he doesn't ever." The argument can be made that "he doesn't" is the best translation but neither translation is incorrect. (Because we should always translate for meaning, not word-for-word.)

You know how this could be solved? In the first question, instead of giving the English translation "He doesn't ever go to bed before midnight" you could give "He doesn't go to bed before midnight anymore."

I understand what the quiz makers were trying to do. If we see a sentence that includes "jamais" we think "never." So they wanted us to think, "Well, the sentence doesn't include "jamais" so it must not mean "doesn't ever." The problem is that this sentence does mean "doesn't ever."

Again, I got the question right. It's just a poorly-designed question. It could easily be improved, but sadly Kwiziq doesn't improve anything based on feedback from students.

I beg to differ. The two sentence "He doesn't go to bed before midnight" and "He doesn't ever go to bed before midnight" do not mean the same thing.

The former can also mean that he usually goes to bed before midnight but today he decided not to. Only the second sentence says unambiguously that he NEVER goes to bed before midnight.

The problem is that sometimes one gets a certain context stuck in the head, to the exclusion of all other possibilities.

Regarding your comment that "Kwiziq doesn't improve anything based on feedback from students": you can't have been around much on this forum or you don't read many questions and responses. Because I can point to many instances, where confirmed errors are acknowledged and corrected. But I guess it doesn't make sense to jump and change things based on a single opinion which is still under dispute.

Janet, in my view you have missed the point. In French, when  ne…jamais is meant, it will be used. Hence in French ne…pas is not the same as ne … jamais. 

If you free translate ne .. pas  to include ‘doesn’t ever’ or ‘never’ in English, then you are deciding that English is wasting words, because ‘doesn’t ever’ or ’never’ adds nothing to the English sentence. If that is your view, so be it. I disagree. When we English speakers add ‘never’ or say ‘doesn’t ever’ it is for a reason, pretty much the same one that leads French speakers to distinguish between ne…pas and ne …. jamais, I suspect.