Billing Number Range Assignment

Hello,

I have this requirement to assign a number range to billing document based on below conditions:

1. IF ( region code at Header Level is same as region code at Item Level ) AND ( Account Assignment Group is '08' ), then a new number range to billing document. ( Ex: KAA9000000 - KAA9999999 )

2. Otherwise, the already used number range will be taken. ( Ex: KAA8400000 - KAA8499999 )

In both the cases, the prefix will be same.

The problem is there are already so many enhancements, and the Number Range FM is NUMBER_GET_NEXT. This FM picks from and updates to NRIV table. Below is the code in FM. Now, what I need is to put a condition before in the select statement.

  IF i_gst_odn EQ 'X'.

    SELECT * FROM j_1ig_ofnum INTO TABLE lt_j1ig_ofnum

      WHERE bukrs = i_bukrs

        AND bupla = i_bupla

        AND docclass = i_docclass

        AND ( VALIDFROM <= i_PostDate and VALIDTO >= i_PostDate )

        ORDER BY PRIMARY KEY.

    IF sy-subrc EQ 0.

***Sort the number range configuration table in descending order by fromdate  "2535105

      SORT lt_j1ig_ofnum BY validfrom DESCENDING.           "2535105

**      LOOP AT lt_j1ig_ofnum into wa_j1ig_ofnum.

      READ TABLE lt_j1ig_ofnum INTO wa_j1ig_ofnum INDEX 1.  "2490434

      IF sy-subrc EQ 0.                                     "2490434

        CLEAR:wa_ofnum_tw_2,lv_from_number.

        MOVE-CORRESPONDING wa_j1ig_ofnum TO wa_ofnum_tw_2.

        SELECT SINGLE * FROM nriv INTO wa_nriv

        WHERE object    = gst_nr_object

          AND subobject = wa_ofnum_tw_2-subobject

          AND nrrangenr = wa_ofnum_tw_2-groupnumber

          AND toyear    = i_gjahr.

       lv_from_number = wa_nriv-nrlevel+10(10).

       IF lv_from_number < wa_nriv-tonumber.

          CALL FUNCTION 'NUMBER_GET_NEXT'

               EXPORTING

                    object                  = gst_nr_object

                    subobject               = wa_ofnum_tw_2-subobject

                    nr_range_nr             = wa_ofnum_tw_2-groupnumber

                    toyear                  = i_gjahr                    "2490434

               IMPORTING

                    number                  = lv_gst_number

                    returncode              = lv_retcode

               EXCEPTIONS

                    interval_not_found      = 1

                    number_range_not_intern = 2

                    object_not_found        = 3

                    quantity_is_0           = 4

                    quantity_is_not_1       = 5

                    interval_overflow       = 6

                    OTHERS                  = 7.