Swami Desikan says it is doubtful for the prapatti to bear fruits if one has an association with demi-gods until the last breath.
Nammazhwar states if a prappanan surrenders to Emperuman at the final stage by disassociating with demi-gods, without a doubt Emperuman certainly accepts the prapatti and grants salvation. (‘’mALumOr iDatilum vaNakoDu mALvadu vaLamE’’)
It is not wrong to do prayaschita prapatti immediately after realizing one’s offense; if another offence is committed, one can do another prayashcitta prapatti; but it is important that one should not repeatedly commit the offense and must refrain from committing sins. Elders perform prayaschita prapatti for everything only once invoking the Dwaya mantra.