I think it depends on the situation of what's being recorded.
I remember a few weeks ago, I had a timer set up to record reruns of Akame, since CN was airing multiple episodes back-to-back in a 4-hour marathon. According to the Daily Schedule page of my Hopper, it only showed 1 tuner (the green timer symbol icon) being used for each 30-minute episode that was being recorded. Normally if it was a different program or a different channel being recorded, the schedule page would show either the blue icon or the purple icon to indicate a 2nd or 3rd tuner would be used, due to the 4-minute overlap between recordings. But in this case, it used just the 1 tuner to record from 11:58 pm to 12:32 am, then from 12:28 am to 1:02 am, etc. all throughout the 4 hours.
So apparently sometimes the Hopper is smart when it comes to tuner usage...