Either of the two fixation appears to be incorrect in my opinion.
Promotion is due on 01.03.2012, so it will be beneficial for the employee to opt for pay fixation on 01.07.2012. (Ref: No. 2728-F dated 07.04.2009)
Now Pay fixation will be as follows:-
Basic Pay as on 30.06.2012: Rs. 6790 + 2600 = Rs. 9390
Basic Pay as on 01.07.2012 after awarding promotional increment and higher grade pay: Rs. 7080 + 3600 = Rs. 10680
Basic Pay fixed on 01.07.2012 as per minimum pay in the payband = Rs. 7100 + 3600 = Rs. 10700
Basic Pay after normal annual increment = Rs. 7430 + 3600 = Rs. 11030
Basic Pay on 01.07.2013 after normal annual increment = Rs. 7700 + 3600 = Rs. 11370
Basic Pay on 01.07.2014 after normal annual increment = Rs. 8050 + 3600 = Rs. 11650
Basic Pay on 01.07.2015 after normal annual increment = Rs. 8400 + 3600 = Rs. 12000
Next annual increment on 01.07.2016