hi Hu Po,
in your grouping formula you use a limit of 6. this means that only 6 records will appear in each group which then means that you can only have 6 columns and 1 row.
if you want 6 columns and 4 rows you need to use a number of 24 for your group. you also must ensure that the proper data is in each group. please see the second half of my blog post here for an example.
it is very important that you ensure that your groups have the proper data in them in order to produce the cross-tab formatting.
steps to try to get this to work in your report:
1) change the number in your grouping formula to 24
2) order the report by the C1,C2,C3 field in the report sort expert
3) order the report by the date field in the report sort expert
-jamie