DATA dd like L_S_FIGL4_BIW-BLDAT.
DATA ddper like L_S_FIGL4_BIW-BLDAT.

    dd = L_S_FIGL4_BIW-BLDAT.
    IF dd < '1985' OR dd >'2030'.
       dd = L_S_FIGL4_BIW-FISCPER.
       ddper = dd+5.
       dd+4 = ddper.
       dd+6 = '01'.
       L_S_FIGL4_BIW-BLDAT = dd.
    ENDIF.