If one will not be able to utilise balance accumulated ITC (i.e., after calculation of refund amount u/r 89 (5) as per old formula) for past period/s for foreseeable future, one can definitely try to get higher refund by claiming that the subject amendment should be treated as retrospective.
However, following stumbling blocks needs to be understood before marking such litigation-journey which is expected to be long-drawn battle, having its own costs and with uncertain outcome:
A. Amendment in Para 8 (d) is not made by way of adding an explanation.
A1. Explanatory route was used in many amendments (For example: Para 3, 8 (a), 8 (c)) in very same Notification 14/2022 dt 05.07.2022
B. In very same Notification, there are many amendments (For example: Para 7, 9, 10, 19) which are specifically made retrospective.
B1. But, such amendment as retrospective, is conspicuous by its absence in the notification about the subject matter under discussion here.
C. So, using the very same reasoning given by Supreme Court in case of UNION OF INDIA & ORS. VERSUS VKC FOOTSTEPS INDIA PVT LTD. [2021 (9) TMI 626 - SUPREME COURT], it is possible to argue that GST council, after due consideration, has chosen to give such benefit only prospectively.
But, considering large number of adversely affected tax-papers, I do hope that Govt. comes up with clarificatory circular or amendment etc. to give effect of such amendment as retrospective.
Govt. should also give similar relief for ITC availed against capital goods too, both for past and future period (with treating life as 60 months, if it wants to avoid misuse, as done in Rule 43)
All this will be in spirit of ease of doing business, in my view.
These are strictly personal views of mine and the same should not be construed as professional advice / suggestion.