The guidance on transition makes it clear that a PIN does not “count” as “commencement” for the purposes of the transitional provisions. On this example, if a PIN was published in August/September but the actual Tender Notice is published on or after 28 October 2024, the contract will be regulated by the new Act.
There is one small exception, which is where a PIN was published and used as an actual call for competition to start the procurement, then the PCR 2015 will continue to apply. This way of using a PIN ceased to be possible from 26 March 2023 though, so this scenario will be a relatively rare one.