I have found, in my study of officer promotions and transfers, that there was a regimental number (i. e. received at the time of entry into the regiment). These were used for regimental internal documents and reports. A second numbering was shown in the various spiski, Stabs-officer (i. e. field grade) and General officer grades. These appear to change when an officer enters these grades. It is unclear to me as to when, or if, the numbers change when someone on a list is deceased or retired. I have examples of a change in numbering when higher numbered individuals are no longer in the spiski, but this does not appear to be common. Perhaps it was done periodically?
I will try to provide concrete examples for my master database of Russian officers of the Nap period this evening.
Take care my friend,