I struggled to follow the thread at the other place, so will return there when I am more with it.
Like everything to do with ME there is no straight forward answer to the question of cycles in relapsing and remitting forms of our condition, at least for me.
I suspect there are for me a number of cycles happening at once, but it is hard to say what relates to external factors (my activity levels, PEM, other health factors and environmental factors) and the inherent nature of the condition.
There are daily variations, weekly and monthly variations and changes over years and even decades.
My initial onset was sudden (Glandular Fever), I can pin point it to a specific time on a specific day, with subsequent off work for two weeks/at work for two weeks for a number of years till I went half time at work. Then gradual improvement for several years until I believed I was fully recovered. This later turn out to be remission, albeit complete, rather than a recovery. Over time I increased what I was attempting to do.
Then after a couple of years I had a dose of flue and a severe relapse, leaving me more impaired than the initial onset. A number of years mainly bedbound, forced to stop working and then started gradually improving overall though with ongoing shorter term ups and downs. Through not approaching premorbid functioning. There was a further more significant sudden relapse following a day of physical exertion, that returned me to being bedbound. After several years, having completely cut back on any commitments, again there was gradual improvement.
Then I started doing more again and took on other commitments, this improvement continued for a number of years with shorter term ups and downs. This time my next relapse was gradual, taking me over two years to reach my most impaired [to that point], deterioration continued until all commitments were cleared and practical support for daily living activities were sorted. Slow improvement with ups and downs is where I am currently at.
Trying to transfer this into a graph of say time not lying down each day or a graph of how I rated my health would not produce a tidy or smooth curve.
I suspect that all others things being equal if I reduce my activity to below my energy envelope at that time there is gradual spontaneous improvement in the underlying condition, however this is precarious and other infections or over exertion can trigger relapses, however each major relapse is worse than the previous with more symptoms involved and that each phase of remission involves less improvement than previous remission phases.