planned, commitments, actual and budget values in PM order

Dear all,

I have a question regarding planned, commitments, actual and budget values in PM order.

Our requirement is warning message to appear when planned + commitment + actual costs exceed order budget and order must be returned to particular User status.

To be clear - our budget is on order level and the maintenance process will be managed by User statuses – created /creator fills required work, services and materials/, then few levels of approval, then Budget + Release. The budget will be Planned costs + % tolerance /e.g. 10%/.

If after release the maintenance work needs additional services and materials which exceeds the budget and the 10% buffer, the warning should appear and order must be returned to user status created and to pass levels of approval again.

Do you have any suggestions? Is it possible to be done by exciting user exit?