We have understood the requirement that the system should validate and allow a negative revision budget value up to the value shown in the Remaining budget column. For example, if the original budget is 15,250, the consumed budget is 6,336.80, the committed cost is 3,000, and the remaining budget is 5,913.20, the system should allow the user to revise the budget up to -5,913.20. If the user enters -5,913.21, the system should give a validation error.

It can be developed and implemented to each legal entities separately on the basis of bullion "Stop Negative Project budget revision" on PMA module parameter page under cost control >> Budget Control.

I have raised the MS ticket and they have confirmed that there is no validation on budget revision against the remaining budget by default.