sort your IT by f1 f2 f3 f4 f5 then
loop at it into wa.
if(wa-f1 = lv_f1 and wa-f2 = lv_f2 and wa-f3 = lv_f3 and wa-f4 =lv_f4 and wa-f5 = lv_f5).
here you add amount and put all fields into another internal table IT2.
wa2-f1 = wa1-f1.
wa2-f2 = wa1-f2.
wa2-f3 = wa1-f3.
wa2-f4 = wa1-f4.
wa2-f5 = wa2-f5+wa1-f5.
endif.
modify IT2 from WA2.
lv_f1 = wa-f1.
lv_f2 = wa-f2.
lv_f3 = wa-f3.
lv_f4 = wa-f4.
lv_f5 = wa-f5.
endloop.