Result showing zero values

Hi,

In report selection we have sales org, period(e.g M (month)) and after written below customer exit code for zcreatdate to calculate last month 1st date to last date(e.g. 1/10/2015 to 31/10/2015).

WHEN 'zcreatdate'.  

   Data : l_val(2).

   DATA : I_SEL_OPT type standard table of RSDSSELOPT ,

          s_sel_opt type RSDSSELOPT .

     IF i_step = 2.

       LOOP AT i_t_var_range INTO loc_var_range WHERE vnam = 'ZRPRD'.

           l_val = loc_var_range-low.

         if l_val <> 'DR'.

         perform get_dates1 ( In this function calculate last month 1st date to last date(e.g. 1/10/2015 to 31/10/2015) and  it passes to s_sel_opt)

                           Tables I_SEL_OPT

                            using    l_val.

      read table I_SEL_OPT into  s_sel_opt index 1.

               l_s_range-low = s_sel_opt-low.

         l_s_range-high = s_sel_opt-high.

         l_s_range-sign = 'I'.

         l_s_range-opt = 'BT'.

         APPEND l_s_range to e_t_range.

         clear loc_var_range.

         endif.

      endloop.

But after executing query we getting zero values.

Here i have doubt for ZRPRD infoobject just maintained values manually like M(month),Y(Year), Q(Quarter), etc..

Because for user input for selection query to calculate dates based on periods(M,Q etc). For period we don't have data in info cube.

For this reason we not getting out put or any other?