So you predict that when a person gives reasons for eir decisions, those reasons should always be correct. It also predicts that our decisions will usually be those that would be arrived at by logical reflection.

Stating your opponent's argument in absolutist terms and then rejecting it in support of your theory is not a good method ;). Did you read the "Good and Real" description of the C function? It's not really to "think logically" but being a selectively active supervisor process IIRC. The override might be seldom, but important.

Almost unquestionably there is a lot of rationalization and self deception going on, this is crystal clear from famous split-brain experiment. It's just not obvious that this is the raison d'etre for consciousness, esp. in light of lacking a plausible evolutionary path for this as was pointed out by several people.