Surely PADI is part of PPPoE not PPP itself iirc?
If you have a separate modem, PADI will be passed through to the router (or PC if you are using that to handle PPPoE).
I presume the "integrated" in the SIN means a combined modem/router in one box? I don't see why it makes any difference whether there's one box or two. PPP gets based through to the router anyway even in the two-box scenario. Bit confused as to why the SIN says that. It seems to imagine the presence of modems that handle the entire PPP or even PPP plus PPPoE themselves internally and only pass through the payload to some router, so these obviously need to be relieved of the requirement in the SIN as they can't be expected to report the info through.