From reading the thing, it sounds like auto-aim requires some kind of lock-on period. It might be a function of one of your biomods.
Supporter of the "a happy fredster is a wet fredster with jumper cables attached to his nads" fanclub.
"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." -- Bertrand Russell (I think...)