Model calculation for a Pre-2006 HSG-II Pensioner retired in 30.06.2004: 

1) Basic pay on date of retirement on 30.06.2004: 7850/-

2) Notional pay fixed on 1.1.2006: 7850 x 1.86 = 14610/-

3) Adding appropriate GP: 14610 + 4200 = 18810/-

4) Notional pay fixed on 1.1.2016: 18810 x 2.57 = 48341.70

5) Notional pay as per Pay Matrix of 7th CPC at Level 6: 49000/-

6) Revised pension from 1.1.2016: 24500/-

7) Basic Pension originally fixed under Option 2 from 1.1.2016: 22581/-

8) Difference in Pension (between column 6 - 7): 1919/-

9) Arrears due from 1.1.2016 to 30.04.2017 for 16 months:

1919 x 16 = 30704/- + DR due from 1.7.2016 (228/-) and 1.1.2017 (462/-) = 690/-;

So total arrears = 30704 + 690 = 31304/-.