I somehow doubt _cat/indices is showing me wrong information regarding store size.
I have two indices - giitran_with_message and giitran_without_message.
Now both have have almost the same document. Each one has 1000 docs. The only difference is that giitran_with_message has one extra field - message.
Now as you can see from response of _cat/indices, the primary store size of the index (giitran_with_message) with extra field is smaller than the index without message field even though store size seems correct.
Normally primary store size should be half of store size since we have one replica. It looks logical for giitran_with_message ( ss= 505.1kb pss=252.5kb) but not for giitran_wthout_message (ss =426.8kb pss = 281.2kb). Any thoughts ?