@ Krushna,
In ami database there is option of "base time interval" wherein you put tic, seconds till EOD, if you have opted for seconds or tick data and after rtd has printed candles in ami and then if you back fill over the same data from data table which is of 1 minute interval, you are bound to get slight variations in the candle shape, but the opening and closing should be same, this is what I have noticed when I back fill from DT over previous rtd printed candles.
I do not use NT, so no comments on that