every transfer i've had, i've been started on the progesterone support prior to transfer. when using crinone, it was one a night (the 8%), starting the night before the transfer. it's possible it's been done differently this time than your previous trasnfer if there has been evidence that your natural progesterone level after EPU has been a little low... i guess having support a little earlier, if it helps with the outcome, is always worth the effort!