the best approach in this type of situation is to at least sometimes use anabolic steroids immediately upon resuming mass gain, rather than waiting. This is from the perspective of the same total amount of use: if it were more use, then obviously more would do more, but there seems to be another factor here as well.
While oral anabolic steroid when present in the system help muscle cells develop and maintain higher levels of contractile protein and generally greater size, this does not have to be their only benefit to muscle cells.
Most probably remember from biology that cells have a nucleus, which controls production of mRNA and therefore of proteins, and most think of cells as being tiny.
Muscle cells however stretch the entire length of the muscle ! For this reason, it would not work for them to have only one nucleus. The cell is much too long and too large overall for a single nucleus to supply. Instead, muscle cells have very many nuclei per millimeter of length.
The potential size of a muscle cell is definitely limited by the number of nuclei in it. Once your training and nutrition has taken you to where your muscle cells are as big as possible for the number of nuclei they have, those cells will not get larger yet. The cells themselves cannot “grow” new nuclei.
However, their number of nuclei does not have to be fixed. Training can stimulate fusion of satellite cells into mature muscle cells, permanently increasing the number of nuclei. However, only so much of this occurs before further such increase becomes slow or essentially stops.
Another factor which can trigger fusion of satellite cells into mature muscle cells is use of anabolic steroids. Besides providing benefit at the time of use, permanent benefit results from the increase in number of nuclei.
Now, what about situations such as yours?
While natural training can add nuclei from the untrained state, and probably while progressing to personal records of muscle size, I don’t think that regains in the natural condition do this. The natural trainer who loses muscle size will regain more quickly than he gained originally, but will have no permanent advantage from multiple loss/regain cycles.
In contrast, when anabolic steroids are used from the start of regain periods, the natural balance point appears to become higher and higher over time. It might be the case that when regaining naturally, as the muscle cells already have enough nuclei, there’s no trigger for fusion of yet further satellite cells, but where anabolic steroids are used, this does occur.
Enough of the theory, as it’s unproven! Other than the facts regarding number of nuclei and fusion.