Intial questions were mostly on testing concept. But at later part some senior person stepped in with on the fly questions with all the time fluctuating requirements on estimation. It was answered properly but he had some other perception of estimate. Though both landed at very very close estimate. But not sure why he was adamant on his estimate process only. It appears , either he did not know another technique or just a hard shell on his way of estimation. I would say, it is waste of time here irrespective or selection/rejection.