I take it a cycle is just 100% of use no matter where it happens on the battery span? Eg 100-40% and then 80-40% is one cycle
Just to make that super-clear, the answer is yes because 100%->60% = 60% and 80% -> 40% = 40% for a total of 100%, or one cycle.
[doublepost=1482944608][/doublepost]
If you haven't already I would run the battery from 100% down to 1% during normal use. Ok it's not particularly good for batteries to run them down low, but its a bit of a catch 22 as it can help with calibration. It won't do any harm doing this just occasionally if you usually charge your phone before the battery gets low.
Usually you get the equivalent of around 5% battery before they drop to 99%. From a full charge my iPhone 7 usually does around 40 minutes useage sitting on 100%
Cheers
Yes to this...Li cells do not like to be hammered: run down to very low or charged up to very high amounts. An occasional run down to 5% or what the phone sees as 0% is not going to be a long term issue but I wouldn't do it often.
The other side of this is that most of us replace phones before this becomes an issue. My older (28 yo) son has an iPhone 5 that really has got battery issues, but it's been used continually for four years and at this point neither the phone (economically speaking) nor the battery (chemically speaking) owes him a nickel.