Clear BPS variables values

Question

I wrote an ABAP program to clear BPS variables values defined for the user.
      DATA:
      lr_variable TYPE REF TO cl_sem_variable.
* Get variable instance
      CALL METHOD cl_sem_variable=>get_instance
        EXPORTING
          i_area       = I_AREA
          i_variable   = 'ZPVDEP' "z_v_var
        RECEIVING
          rr_variable  = lr_variable
        EXCEPTIONS
          not_existing = 1
          OTHERS     = 2.
      IF sy-subrc <> 0.
* do s.th., eg send a message
        EXIT.
      ENDIF.
* delete the restrictions
      CALL METHOD lr_variable->set_user_restriction
        EXPORTING
          i_user   = sy-uname
          i_delete = 'X'
        EXCEPTIONS
          failed   = 1
          OTHERS   = 2.
In BPS0:
1. i restrict the variable with some values
2. execute planning function to clear the variable values
    But the restriction remains.
3. When i do /nBPS0 the variable restriction clears
As far as i understand the problem is in buffer. How can i clear buffered values of the variable in ABAP program?
i tried to call  method CL_SEM_VARIABLE=>RESET_BUFFER.
but it doesn't work.
Thanks

Answer 1

Also i try such an ABAP code
      SELECT *
      FROM upc_var_cha_sel
      INTO CORRESPONDING FIELDS OF TABLE it_var_cha_sel
      WHERE    area    = I_AREA
           AND var     = ls_exitp-CHAVL
           AND varuser = sy-uname.
      IF sy-subrc = 0.
        DELETE upc_var_cha_sel FROM TABLE it_var_cha_sel.
        CALL FUNCTION 'DB_COMMIT'.
      ENDIF.
      REFRESH it_var_cha_sel.
      SELECT *
      FROM upc_var_cha_act
      INTO CORRESPONDING FIELDS OF TABLE it_var_cha_sel
      WHERE    area    = I_AREA
           AND var     = ls_exitp-CHAVL
           AND varuser = sy-uname.
      IF sy-subrc = 0.
        DELETE upc_var_cha_act FROM TABLE it_var_cha_sel.
        CALL FUNCTION 'DB_COMMIT'.
      ENDIF.
But the problem is the same
In BPS0:
1. i restrict the variable with some values
2. execute planning function to clear the variable values
But the restriction remains.
3. When i do /nBPS0 the variable restriction clears
Thanks