Your assumption appears to be inaccurate according to the info below; in wet conditions the distances would most likely be the same. See:-
Almost the same, but the manual braking still shows some improvement in braking.
I probably could have used a better word than "assuming". I meant "providing". I was trying to say that Autobrake deceleration rates are targets only. Depending on how wet the runway is, these target rates won't be achieved.