Hi Rijuraj,
I am not aware of any standard solution without FM. You probably can develop an interface from the FI-TV estimated cost into the order plan, because ROP can be treated as commitment in PS AVAC.
Besides a hard stop for budget availability control does not do any good, eventually it prevents a recording of facts that took place already in a past and cost is incurred. You should have a soft reaction with warning + email.
Regards,
Paulo