I like your distinction, and think there is an important difference to be made between A and B. But I don't think you've framed B quite correctly. For example

I like your distinction, and think there is an important difference to be made between A and B. But I don't think you've framed B quite correctly. For example, what would be the difference between "I am confident" and "I am 100% confident"? What would be the case for B in which having exactly 65% confidence would be correct? I think both A and B have an unspoken assumption of "and assuming there is no error in our measurement of XYZ, and assuming that XYZ means what we think it means, and assuming there is no other evidence we are failing to consider". Unless one's confidence in these assumptions (and probably some others) is 100%, one shouldn't have complete confidence in any particular course of action.