39 ASF per Level IV (pretty strong ASF contingent, to be fair). But, even though it specifically states that each ASF made up a single Level I (just like vehicles & 'Mechs), it also says they followed standard military doctrine & deployed ASF in pairs.
I'm assuming that it's more likely that it was supposed to be 36 ASF per Level IV (which would either allow for the Level IV to deploy them as a single Level III/36 units, or split them up into 6 Level IIs of 6 units each as needed on the battlefield), but I don't know for sure if that's true or not.
I love how often this question comes up, lol.
I originally assumed it had to be a typo & it was supposed to be 36 but the other 3 columns all come out to total 177 which comes to 39 remaining for ASF.
Now this could have been a typo earlier in the project & someone just adjusted the other #s but who knows.
In my own TO&E I would just add 1 to each of the other 3 columns & use 36, but, then someone of the forums pointed out that # every division will not match those perfect Greek-Alpha designations & that the #s at the Division level could be "Averages".
So Option #2 then is to think of them as something like 36 for every OTHER division & 42 for it's counterpart giving you an average of 39.
Another thing to consider is there were not supposed to be any "PURE" Level-3's.
FM:CS states that all L-3's (Battalions) were Combined arms, but, even there we have a few Scenario Books that do show a few on some TO&Es.
So instead we should again assume that Pure L3's were just "Rare".
Also, every L3 was noted to have ASF support, so that would be a
minimum of 2 ASF for every L3, since they are always at least deployed in pairs of wingmen.
Finally when it comes to L-2 formations (Demi-Companies) of 6 units, PURE was "Common" while Mixed was "Un-Common or Not-Rare".
Again, for my own personal fluffed TO&E's, I like to start out each L-3 with 4 Pure Units, 1 each from Mech, ASF, Vees, & Infantry.
Then I had the last 2 as added Pure, or Mixed units as needed. If I went with less than those base 4 "Pure" units it was normally by Vees getting mixed w/ Infantry.
I generally like to keep the ASF grouped into Pure L2 formations, but, if you have some odd #s then pairs assigned to HQ or Recon L2's seems to be the most logical place to put them outside of Pure ASF L2.