The following clarifications have been made in Rule 3 of G.O. No. 181-SE(B)/5B-1/09. Dated, the 8th October, 2009 in the link ibid.
_____________________________________________________________________________________________________3. Fixation of pay of the employee after obtaining non-functional movement (18 year’s benefit) or non-functional increments (10/20 years of service) and other issues :
(i) The Finance Department , Government of West Bengal in its Memorandum no. 2728-F dated 7th April, 2009
(Para-2) has clarified the matter as follows :-
1. In the case of non-functional movement (18 year’s benefit) or non-functional increment (10/20 year’s benefit) an employee may opt for the same on the date of entitlement or on the next 1st July, the date of accrual of annual increment.
2. In case the employee opts for the benefit on the date of entitlement he/she will get one increment on that date, but he/she will not be entitled to next annual increment on the next 1st July unless he/she completes 6 months of service. In other words – if the date of entitlement falls during 1st July to 1st January, the employee after having the benefit of one additional increment, on the date of entitlement, will get annual increment on the next 1st July,
but if the date of entitlement falls during 2nd January to 30th June, the employee after having the benefit of one additional increment, will not be entitled to the annual increment on 1st July of the same year; he/she will,however, get the annual increment on the 1st July of the next year.
Please have a look at the highlighted portions.
As your date of increment falls between the period of 2nd July to 1st January, you should get the increment on the same date of entitlement i.e. on 09-12-2013 and your next increment will fall due on 01-07-2014.