Hi.
Indeed im not sure if this OSS work well, i didnt see this problem in the last years. In 2010 i was working with IS CWM and face this problem. We write SAP support and they correct our problem, i dont remenber exactly the program they give us, but this was a special case because this is a Industry solution.
Do the following, check oss 724536 - Changing the base unit of measure - program
In this OSS you find z program ZML_ADJUST_MEINS.txt
If dont work, its a good idea to write sap support, maybe there is a bug in oss 1580829
good luck
arturo.