Dressing for war.
I have re-read the "About this guide" a number of times & can't find a reference to the large print numbers in brackets after, fore example Vielle Garde (9,1,2) , Moyenne Garde (2,3) or Infanterie Legere (10,2). The intro refers to the (#) after the historical unit is the maximum number of units in any single scenario. I took that sentence to be referring to the number after the unit name. eg 17th Regiment d'Infanterie Legere (3). The multiple numbers in brackets has me confused.
What say you?
The numbers after each historical unit entry are the maximum number of game units required for the scenarios – as you correctly understood.
The numbers included in the headings of each section are a summary total. So, for instance, if the total maximum number of Russian Pehotniy Units among the scenarios is 78, you'll see (78) in that line.
But, if there are multiple numbers separated by a comma, that is simply listing the number of Units for different Unit types that all fall under the same heading. For instance, Russian Artilleriya (47,39,2,5,17) is 47 Artilleriyskaya (Artillery Units), 39 Oboz (Train, i.e. Reformation Areas), 2 Donskaya Artilleriyskaya (Don Cossack Artillery Units), 5 Oboz (Cossack Train), and 17 Pionery (Pioneer Companies, i.e. Specialty Units).
We tallied and included them simply as a matter of course. They will only be primarily useful to players who intend to play out the entire book/Campaign since they are maximums across the entire swath of the scenarios for every Unit type.