the register by accepting. ...
Of course, one down side to this (and I know that the OP was probably not suggesting this as the better approach) is that if you don't match what you think you spent, you might 'accidently' accept transactions that weren't yours, or are changed from your bill (I've had that happen when I think I've paid $xxx to a restaurant after adding the tip, and the amount they actually post to my account is different.)
Of course I suggest version 'A', which is you MANUALLY add your charges, and then download/accept after verification that you agree with all of the items appearing on the OSU.