How to combine two rates

Dear Experts,

We are newly implementing EBTAX on test instance and I have done all mandatory setups of taxes.

Currently we create two rates which are 8% and 2% and both taxes are working fine individually but client have new requirement they want both the tax rates calculate combine.

Like invoice line taxable amount is 1000 and 8%+2% are combine charge on invoice.

RESULT 100

Please guide us how we can fulfill this requirement

E-Btax Setup detail document are find in the attachment.

Your Thankfully

Ayaz