Questions about subtitle choices

I’ve been reading through the site and the forum, but I still have a question about the subtitle options.

I’m doing the trial of Pro, so I see there are options for Human vs Machine subtitles. I assumed that the human ones were the ones provided by Netflix, and the machine ones are auto-generated from voice recognition or something. I’m trying to watch a show that’s originally in English, and I’ve turned both the audio and the subtitles to Portuguese. I noticed when watching this originally in Netflix itself that the Netflix-provided subtitles are quite different from the audio at times, likely to simplify. So I figured hey, maybe this is where the machine subtitle option could come in handy. However, it looks generally the same as the other, and also doesn’t match the audio. So where does this come from, and where’s the benefit if it doesn’t match the audio?

ETA: Ah, I misunderstood this function a little. It doesn’t get anything from the audio - it’s translating the subtitles. So if the subtitles don’t match the audio, then whatever they’re translated to still won’t match. I tried setting the subtitles to English CC, and then theoretically I could use the machine translation to get an exact Portuguese translation of the real words being said…in English. But since the Portuguese audio doesn’t exactly match the English audio, this still doesn’t help me. Guess I’m SOL on this one, but figured I’d leave the question and put this clarification up in case it was useful to anyone else who’d also misunderstood.