Process Validation exemption

Good day. I understand that Process Validation (PV) needed to be done for 3 consecutive batch for every new products and existing product that undergone changes.
Just curious to ask, if example that registration batch size is 300kg, and PV is done. And intended to do another batch size of lesser or higher than 300kg, with all the equipments used same, can i skip the PV again for the new batch size? And whats the batch size range if i were to need to exclude for PV ? Any guide that can help? As all guide is telling that all batch size needed to do PV if it is different with reg batch size. Thanks