Dear Malathi That was avery pertinant observation which for whatever reason did not attract much discussion...
Kavirim Mainthan is set a few years after PS Nadhini is a old..RRC is Old..Vanathi is old Chinna PaZhuvetarayar is senile so is sambuvarayar is almost mad....but Kandamaran is still in the prime of youth doesnt add up as you rightly pointed out