The mentioned publication also had the partial figures for different forms of military service, the numbers I have presented refers to the total of military personnel in active service, by military branch.
One possible explanation for the difference between the sources may be related, precisely, with the 4 months short-term military service. For example, if the Army had a key number of having 20.000 conscripts a year, that means that they would incorporated a total of 60.000 conscripts, 20.000 from January to April, 20.000 from April to August, 20.000 from August to December.
Other explanation may be the difference between the authorized figures and the number of personnel that was really in service/incorporated.
I will try to read the publication (LOURO (coord.) (1994)) in more detail to see if it can offer some more explanations.
