Tax Type

Hi all ,
Need to update a new tax type with custom calculation.
Now we are calculating by the below method::
Gross : 10000
IGST 9% : 0
CGST 9% 900
SGST 9% 900
Total 11800

New Tax calculation method is::
Gross : 10000
IGST 9% : 0
CGST 9% 900
SGST 9% 900
TCS on Sale of Good @ 0.75% 8.85 (Gross + GST) *0.075%
Total 11808.85

How this can be achieved. I tried manual calculation it is ok, But it need to generate automatically.
Pls Help

Easiest is to create a new tax type TCS @ .0885% and it will work.

Yes i created the tax code. But i need to calculate the (Gross+GST) with 0.075%(TCSValue), then total the Gross+Gst+Tcs value.