While I don't think it's difficult to infer that AMS should handle iATMs like streak launchers, I disagree that it's explicit.
As you pointed out, WoR pg201 says,
The iATM’s targeting system functions in a similar manner as a Streak launcher
while TW pg 129 says,
If the missile weapon is a Streak launcher, treat the
launcher as though the controlling player rolled an 11
on the appropriate column of the Cluster Hits Table, then
apply the –4 modifier to determine how many missiles
struck the target.
If TW said something like, "if the missile weapon targets like a streak launcher" or if WoR said "treat the iATM like a streak launcher" then I think it's clear, however as it's written I feel like the authors intent needs to be inferred.
I understand that this is fairly nit-picky and it can be treated as such; I've just been burned by making assumptions about rule interpretations.