We have concern while processing Contract payments to our Suppliers/Contractors. The system design seems to be more geared to Sales and Customers as far as commitment and payment processing is concerned.

However, Purchasing and Contract/Services Modules are giving very narrow choices in Contract/Services payment processing stages. Consider the following example:

We awarded a Contract for services to a X Supplier for sum of $100,000. Which is the total budgeted amount for the service. The task will be performed in three stages (milestones) as per the Contract/Agreement. Similarly, the payment will be released by stages e.g. First payment say $30,000 on completion of 30% of the work and so on.

But before any payment, we need to create the Contract in Odoo with the full Contract value as a commitment liability not real payment. It should only appear as commitment entry in the system which we cannot find now. Every time we process actual payment, the commitment should be reduced by the same amount of money and real posting takes place in the financial books.

Now, the question is how could we create and control 1) Contract with committed value against payments through the system from beginning to end? 

2) which of the Odoo modules is appropriate to create for such service Contracts.

We would appreciate for your guidance on the subject.