Maint. Provision for Billing

Dear All,

Our customer have special requirement for maintain ace provision at the billing document level. And accounting entries as per below, I tried with creation of new condition type and Accounting key but it's not working. If possible, please guide me to fulfill the requirement.

1. When Delivering Goods to Customer

Accounting Entry:

Dr Cost of Goods Sold 100

Cr Finished Goods 100

2. When billing to customer

Billing price is 150

Accouting Entry

Dr Customer 150

Cr Sales 135

Cr Provision for Projects 15 (10% on 150)

Thanking you,

Regards,

Kamlesh Panchal