You could try something like this...it doesn't need to use Field-Symbols.
LOOP AT P0041 INTO w_p0041.
DO VARYING w_darxx FROM w_p0041-dar01 NEXT w_p0041-dar02
VARYING w_datxx FROM w_p0041-dat01 NEXT w_p0041-dat02.
IF w_darxx IS INITIAL. "EXIT AFTER LAST DATE TYPE
EXIT.
ENDIF.
IF w_darxx = `Z1`.
"your business logic here....
EXIT.
ENDIF.
ENDDO.
"further logic here...
ENDLOOP.
Hope this helps.
Sougata.