Although I have endeavored to enshrine a mindset in Engineering that "Thou shalt not add lot or serial control to items with stock on hand", this hole in the process comes back to haunt me regularly. Please, please, pretty please add some kind of warning or block to IN-B that will help stop this from happening. A high voltage shock to those who attempt to violate this law would be preferable, but I could probably settle for a pop-up. If you wanted to do a really professional job you could give us an SD-Q choice of "Allow add Lot/Serial Control with UOH (Y/N/W)" so that every user site could choose whether to allow (Y) the evil deed, disallow (N) it, or simply warn (W) the offender of impending doom.