Investment orders

Suppose I raise a Service work order for 10L assuming that my budget assigned is 15L. But payment has been made for 2L only. Ideally it should project 10L as Committed Budget and 2L as actual expenses. So that makes 8L as available amount in payment budget. But in my case, when I raise a SWO payment budget shows only 5L as available budget.

What are the additional configurations to be done to address this issue???

Thanx

Shivaji