Hi Pawan,
You`d better declare a another object, say 'Accountant', in this object, have a method used to calculating average, which importing parameters is a itab. In this itab, havd appended this two companies. I think no mater this calculating average method is static or instance, it`s ok, that`s depened on you how to abstract 'Accountant'.
BTW, static method has a small memory footprint than instance .
regards,
Archer