Back when I first started using Splynx (1.2 I think) I noticed that if I want to get Daily Traffic statistics for my users I need the PPPoE session to be ended and restarted at least once per day.
From my last conversation with Alex I think this is still the case in 1.3
The way I forced sessions to be no longer than 24hours was to set Mikrotik PPPoE session limit to 1Day.
This works but provides some small interruption in service when the session is renewing. Because this happens exactly 24 hours after the first connect time, in some situations (eg. first connection or power cut etc.) this reconnect time happens in a peak customer use time.
We had some customers complain about the interruption in service the same time each day so I implemented a script on the Mikrotik PPPoE server to kick off all users at 5am each day.
This was the only way I could see to ensure daily traffic graphs work correctly but there would be no interruption in service for customers during peak times.
The problem with this is that we have since found some VDSL2+ modems can take up to 10 minutes to reconnect PPPoE when the server kicks the session. Even when scheduled to happen at an off peak time such as 5am some customers noticed this large downtime.
This is a design flaw of the modem and not entirely a mikrotik/splynx problem but I wonder if there could be a way to reset the PPPoE session from the radius server (splynx) or some other way to reset traffic accounting each day that will be less intrusive for the customer.