Upload Tax Book Interface - Original Cost

Hi,

    As part of an asset migration I am trying to update the ORIGINAL_COST field via the Upload Tax Book Interface process - but it is not working.

I load a file with the following fields;

TAX_LOAD_ID

BOOK_TYPE_CODE

ASSET_NUMBER

ORIGINAL_COST

COST

DEPRN_RESERVE

YTD_DEPRN

AMORTIZATION_START_DATE

AMORTIZE_NBV_FLAG

POSTING_STATUS

All the fields update the records as per upload file with the exception of ORIGINAL_COST - (note - this is performed in the first period of the migration).

Are there any restrictions on this field, for example - you cannot update ORIGINAL_COST and COST in the same upload. Something that may require it to be loaded separately. Or is it more resolved via a SR.