Account Assignment Model and Templates

Hi Expert,

Please let me know exact difference between Account Assignment Model and Account Assignment Templates. As per my understanding Account Assignment templates we can use FB50 or F-90 or F-60 type of transaction where as Account Assignment Model we can use for transaction F-02. Please give your comments on my understanding.

Please also let me know uses of transaction code O7E3 Program -- Account Assignment Model , Application Item Entry Account Assignment Model.

Thanks in Advance,

Rupen