Let's go by parts:
Carlos Eduardo Albuquerque wrote:
If we have a budget of $ 1000,00 in each month, in January we can only use $ 1000,00. But in February we can use $ 1000,00 + the balance not used in January.
Stop there. What budget scenario do you use?
Two moments? ENTR (not available) and release (available)?
Or one moment? (just ENTR = available budget)
And if we are in june and want to make a PO with due date to november, the system must check all the balance not used from january to november and not consider the budget of december.
The system don't check all balance automatically.
As Eli said, FM/BCS don't have a standart function for that. (Así que estás al horno, -youarein the oven, LOL)