Contract Billing & India Tax Localization

Hi!

Would appreciate any help from consultants with experience in India taxation. 

A construction-industry client based in India is using Contract Billing module (for progressive claims, certification and billing purpose) and needs to handle India tax localisation as well. From what I understand, the localization only works with Sales order module as it makes use of Advanced Pricing feature to retrieve the taxes and cannot do so via Contract Billing. 

Question: How do clients of similar industry handle the progressive billings via SOP? Or if they use contract billing module, how do they incorporate the taxes so that they get captured in the relevant localized tables?