So, in your case it was the quality settings you set that shorten the render time so much. Not the 'Max time (secs)' -10200 seconds are 170 minutes- and obviously not the 'Max samples' count you set either. However, it still does not make much sense to me. I mean, if you set 'Rendering Quality Enable' to On, my understanding is that by increasing the value of the 'Rendering quality' parameter you are putting the quality bar higher and hence making the render time longer. And you set it to 6, which is a high value. And my understanding of how the 'Rendering converged ratio' works from a practical point of view is similar: the higher you set it, the more time the rendering is gonna take. And you set it to 99 percent. And the size of your final renders does not look small either.
What is it that I am missing here? Because I honestly can't understand how with those settings you completed that render under the 1-minute mark. With that said, I started rendering very recently and I don't enable 'Rendering Quality Enable' to make my renders, so it is highly likely that I am overlooking something important in your settings.