Yes, a heavier bullet will create more pressure with the same powder charge. But we're talking about making the same power factor. A heavier bullet will require less gunpowder to make the same power factor. That, in itself, does not say anything about the pressure required to make the same power factor, but published data suggests that the heavier bullet will be able to make the same power factor
with less pressure when using the same gunpowder.
So, a heavier bullet is safer than a light bullet?