Supply & Demand entries going negative



I have a big problem with R3483 (Master Planning Schedule - Multiple Plant) because this make availability to go negative over time.

It created a huge positive "Increase Order Quantity" entry & then I suppose the program made the demand create a counter entry.

After that, there are normal entries (positive & negative), but the program is not being able to satisfy the demand, thus creating a negative availability over time.

Hope someone could help me as is affecting seriously PROD

Thanks a lot