If these are CMSR's from the Revolutionary War, they were created by the War Department by clerks who attempted to copy each name and the associated entry from muster rolls and payrolls and some other types of documents that were then (late 1880s-1890s) in the War Department's files.
They are mostly from Continental Regiments, but there are also extracts from miscellaneous militia rosters when militia units were involved in particular actions.
The clerks did a really amazing job of extracting what the records showed.They copied middle initials if present and legible.Remember that no few of the original documents were created under difficult conditions, and those who wrote them did not necessarily have really excellent handwriting.Many of the documents also had suffered damage from mice, silverfish, water, etc., between the time they were generated and the time the War Department had possession.
The original documents were not generated by the soldiers, but were created by designated persons (Captain, Lt., Ensign, Major, etc.) as required and as possible.Some Regimental records include a really good 'run' of surviving lists, but the Company rosters were only made up every few months.For others there may be monthly payrolls, but only for a year or so of the unit's existence.Some units went under a lot of reorganizations (such as the VA Regiments) and the records stop once they were captured by the British.
There is no way to generalize about how many records might survive for a particular individual (they would vary by the person's length of service in any event).
So if you are thinking to estimate numbers of men involved on the Rebel side, from the CMSRs, you can stop here.Further, many State Troops' rosters are not represented at all in this record group, and most Militias' active duty on the frontiers are not either.