Dear,
You can copy function module COCI_CONFIRM_MATERIAL_CONS into a separate function module, for exampleZOCI_CONFIRM_MATERIAL_CONS and do the corresponding changes.
Also in Transaction O12C you might have to expand the process instruction categories to which you want to assign the special stock indicator by an input value for characteristic PPPI_STOCK_TYPE.
Regards,
R.Brahmankar