He informed me that , as an Iyengar belonging to Thengalai Sampradya, he does not do it as it is prohibited by Ramanucharya.
He told me that the other sect of Iyengars in Tamil Nadu, Vadagalai Iyengars perform the Pitru Paksha Tharpana.
As I am unable to find any authentic source on this, I am posting my views.
Those who know the subject well may quote with source.
In Hinduism there are two paths in terms of Lifestyle.
One is called Pravritti Marga and another Nivrutti Marga.
Pravrutti Marga is the leading of our daily lives , as normally do, by going after the sense objects.
Nivrutti Marga is renunciation of the sense objects.
