Problem in showing some values based on selection in custom report

Hi all,

i have written a report in which i have to show some data based on some criteria. I have to show many fields in output, and some of them are based on logic, consider the situation

Doc. No.              Entry Date          Quantity          Km index              Avg.                                    Text      

20002                    01.04.2014          14.880              2130      (2270-2130/14.880) = 9.40    

20002                    05.04.2014          12.560              2270        (2410-2270/ 12.560) = 11.14

20002                    10.04.2014          15.800              2410        (2550-2410/15.880 )  = 8.81

20002                    15.04.2014          13.560              2550        No Higher KM index              Still Running

i am printing these values based on ducument no, that means in a specified time interval say if someone wants to see the avg. between 01.04.2014 to

20.04.2014, then the result should be shown as shown in above .

Now , what i have done is i have calculated the higher and lower km index, but i am not getting how could i calculate the values shown above.

I have written my code as

For calculating min. and max. values , i have written these code

LOOP AT it_final INTO wa_tmp.
    if sy-tabix = 1 .
    wa_max = wa_tmp.
    wa_min = wa_tmp.
    else.
*    minimum
      if wa_tmp-zuonr < wa_min-zuonr .
          wa_min-zuonr = wa_tmp-zuonr .
      endif.

      if wa_tmp-wrbtr < wa_min-wrbtr .
          wa_min-wrbtr = wa_tmp-wrbtr .
      endif.
*    repeat above IF.ENDIF for each col

*    Maximum
      if wa_tmp-zuonr > wa_max-zuonr .
          wa_max-zuonr = wa_tmp-zuonr .
      endif.
      if wa_tmp-wrbtr > wa_max-wrbtr .
          wa_max-wrbtr = wa_tmp-wrbtr .
      endif.
      if wa_tmp-mng1 > wa_max-mng1 .
          wa_max-mng1 = wa_tmp-mng1 .
      endif.
      endif.
  ENDLOOP.

But i am not getting, how can i get my output as shown above. Attached is the code written for my report.

Please tell me , what should be the logic behind this case.