Is CPF OA to SA shielding still worth doing before 55?

Did the shielding for my mother two years ago, so I know the mechanics. The idea: just before 55, you invest most of your SA money into a short-term low-risk instrument so the SA balance looks low. When you turn 55 and the Retirement Account is formed, it pulls from SA first at the FRS, then OA. With SA temporarily emptied, more of your higher-interest SA stays out and your OA (lower interest but more flexible) fills the RA instead. After 55 you sell the investment and the money flows back to SA earning 4 percent. It genuinely works and my mum kept more in the 4 percent pool. BUT note the SA is being closed for those 55 and above under the recent CPF changes, so please check the current rules before you plan, because the whole shielding logic may not apply the same way anymore. Talk to CPF directly.