Actually, and I HAVE done this before SEVERAL TIMES, what you do is this ; you take EACH tray of DPS and invert it......then you just count the upside down pieces. See, all the mail that is run inverted , which is the majority of it , will then be right side up leaving you with the originally right side up mail now inverted which is the lesser number. You then deduct the right side up pieces from the EOR and THAT'S how many INVERTED pieces you originally had.But that's why I asked!! I'm just curious how I can accurately keep track of that number while I am delivering mail at the same time...