Inquiry about Model aggregation

Max_fore_level and min_fore_level are both 3, which is product family in the forecast tree. Below it, it is item and organization. The forecast is generated at level3, which is product family per the engine log. For example, one product family ATT.T1I3*AB5 has multiple items (product family members). The forecast engine log shows the forecast is done at level3. In this case, the model used in forecasting should also be at level3. Why in MDP_Matrix table, the model is stored at item level (item_id, location_id). I found under one product family, different items are using different models for forecasting. These models