Specified Premises - Goods and Services Tax - GST

Sir/Madam, Revised definition of specified premises are to come into force with effect from 01st April, 2025. When can I file a declaration to opt-in to operate as a specified premises for the FY 2025-26? My client is having restaurant and accommodation under specified premises and was understood by me that it would automatically falls under specified premises and no need to file declaration as per FAQ Sl No 7. But while reading the FAQ No 22, it is asking to submit the declaration. Can I now submit declaration in a mid of financial year? Please advise. As it is manual declaration, what if officer not accepts the declaration?