One suggestion
1.In Loop pass you can make use of field symbols so that you want required modify statement.It will have huge impact in execution time.
2.Remove move corrosponding in loop.
3.Before select add checking for table not initial.
LOOP AT it_new_source assigning <wa_new_source>.
READ TABLE SOURCE_PACKAGE WITH KEY
/bic/fcckjobno = wa_source-/bic/fcckjobno
/bic/fcckjitid = wa_source-/bic/fcckjitid
BINARY SEARCH
INTO wa_source.
IF sy-subrc = 0.
<wa_new_source>-f1 = ....
<wa_new_source>-f2 =
ENDIF.
ENDLOOP.
Let me know if you find any impact in excution time.