Hi Akhil,
According to your description, when exporting to CSV and EXCEL, the two layouts have different behavior, right?
In Reporting Services, when exporting to excel, the matrix and table will be rendered with layout in BIDS. But when exporting to CSV, the matrix will be rendered as a table. It is because CSV rendering extension renders reports as a flattened representation
of data from a report in a standardized. So CSV display data to one-dimensional. This working mechanism is by design in Reporting Services.
Reference:
Exporting to a CSV File (Report Builder and SSRS)
If you have any question, please feel free to ask.
Regards,
Shrek Li