Alan,
Aggregate figures are more than how you mention them to be - they include men on the rolls of the army even if they are nowhere near it - being deserters, POWs (known or unknown) to officers, etc. In other words, the aggregate figures are all the men of the AOT and AOM that SHOULD have been in the ranks but often were not along with those that actually were.
Richard McMurry has determined that the more accurate way to count Confederate troops is using their "present for duty" figures. These constitute men in the ranks, all officers (which "effectives" do not count), men on detached service, men in hospital for small items but who could shoulder a musket if need be, etc. (also not counted in "effectives" figures).
Aggregate figures would count two of Wheeler's cavalry divisions taking care of their horses down on the Etowah River while the army was in Dalton, GA while "effectives" do not and "present for duty" figures should as they could be recalled quickly to the army for action if need be.
McMurry also determined that the CSA "present for duty" figures correspond to Union "effectives" figures for the two armies had different man-counting methods it seems.
McMurry's essay on AOT troop numbers for the Atlanta Campaign appears in "Campaign Chronicles" published by Savas-Woodbury some years ago and it is a very enlightening essay providing a far more accurate set of numbers for the AOT.
greg Biggs