Exactly - at 90% discharge & charge, you might get something like 5-600 cycles before you're into serious degradation (say 200mi x 500 cycles = 100,000 miles). Doing 5 times as many 20% discharges gets you something like 9000 cycles x 40 miles or 360,000 miles.
Nobody is going to drive like that every day, but you can see the effect of deep discharging and the benefit of smaller cycles and frequent charging.
Actually it is 80%, from 10% up to 90%, but I get your point. As I said, I was losing 1 rated mile/week during a period when I was using more supercharging. I think that is a lot. I've lost about 5% (14 rated miles (RM), based on 90%) after 9 months and 9k miles. I tried charging to 95% once to see if the RM would update. I was rewarded with another 1 RM drop.
Since I went to this frequent charging (using Tesla mobile connector, 10kW), using about 25%/day, given my daily commute, I've not lost any rated miles.