For express entry u do medical along with your submission. For PNP yes you wait for IRCC to send you medical request but nowadays with covid many are doing upfront medical (I myself did upfront medical for PNP long time back).IME for PNP and family class sponsorship( PGP) are different procedure where it's required upfront and PGP it's instructions from IRCC. Even for supervisa IME is upfront only. You can't change the process of IRCC. It's your wish if you want medical to be done and if doctor do it to make some money but the reports can't go to the file in process under PGP.
I will confirm with the clinic here in ottawa for PGP.