Dear Shri Narayanan
Appendix-2, of BEPR 1995 relating to Regulation 37 deals with payment of DR to pensioners.
The above Appendix just mentions the rates of DR payable to pensioners who retired under different BPSs. It has not explicitly stated that "the pensioner will receive DA at the same rates of calculation and under the same formula which were in force at the time of retirement".
As pointed out by you, it has also not specified that the pensioners will not be eligible for any improved scheme in future.
However, some among us opine that the above two stipulations are IMPLIED and so any improvement could be extended to pensioners only through an amendment to the Regulations.
If IBA is inclined to shift the pre Nov 2022 pensioners to 2016=100 series
nothing bars them from doing so pending amendment to the Regulations. However, the avowed policy of IBA seems to be avoid extending any new concessions to pensioners that would involve even nominal outgo of funds.
So, they indirectly force the pensioners to seek judicial intervention as UFBU is also disinterested to fight vehemently for the cause of pensioners.
K N RAMANI