FA Tax Book setup - updating Original Cost

Hi Experts,

I am facing following issue when setting up new FA Tax Book: the FA TAX Book has first period as of Jan'20. Corp FA Book has 10+ years data. Once FA TAX Book is setup, we execute Initial Mass Copy. Then users expect to run FA Tax Update to make adjustments to assets in Tax Book (cost related, dep related). Cost related adjustment requirement is to have Original Cost and Cost being update. When we try to do that, by passing values to fa_tax_interface table and running fa tax update cm, original cost is not getting updated, only Current Cost