Sorry, none of the fields in the table are timescaled data, they are summary data. Later versions do not offer any cumulative fields in any table view, only in timescaled views such as Task or Resource Usage.I suggest showing the BCWS data to the cost control person in the timescaled view along with the other timescaled values.
There is not, to the best of my knowledge a method of calculating that data through a custom field in a timescaled view.
It may be possible through VBA, but I am not the person to aid you there, sorry.
If you know VBA, you may try posting to the Microsoft Forum for Programming:
https://social.technet.microsoft.com...ct2010custprog
If you choose to post there, please explicitly state that you are using 2003 as things changed after that release.