VCP/ASCP Resource Run Time Change

Hi all

We have a scenario where we need to change the run time or duration of a resource in the future, as it will have gone through its testing and ramp up and will be sped up to run faster.  I tried by creating another operation record in JDE on the master routing with different effective dates, exported this via the JDE VCP UBE in to the manufacturing.xml file but ASCP does not read the xml as we would expect.  Has anybody had this requirement before and if so how did you manage it in JDE/VCP/ASCP?