Amendment & Miscellaneous
(1) Members of the pre-existing Public Service Commission for the Dominion of India became members of the Union Public Service Commission (unless choosing otherwise), continuing under their pre-existing terms. (2) Similarly, members of Provincial (or joint-Provincial) Public Service Commissions became members of the corresponding State's (or Joint State) Commission, continuing under their pre-existing terms.
This mirrors the other transitional continuity provisions (Articles 374, 376, 377) for Public Service Commissions specifically - ensuring the pre-independence civil service recruitment bodies simply continued as the new Constitution's UPSC and State Commissions, without a disruptive fresh-appointment process.
This is why India's civil service recruitment system had continuous institutional operation through the 1950 constitutional transition, rather than a gap while new Commissions were freshly constituted.