Hi

I have a mikrotik RB1100AH configured to authenticate users in FreeRadius. All is working fine, I do however have concerns regarding Interim updates and PPPoE Session disconnects.
Mikrotik does not support POD (packets of Disconnect) so for my radius server to have stop times I use scheduler in Mikrotik to reboot the router every night at 12. The PPPoE sessions then drop and I get stop times.
I have set the interim updates to 10 min and by monitoring the sessions on freeradius I can see that the updates are working. My concern is that as soon as a the router reboots at 12 every night, upon restart it dumps usage amounts to the radius. This is random. Sometimes these values are Gigs of data. Why exactly is this? Surely the data cannot be more than 10mins of usage as the interim updates are supposed to sort this. Is the accounting data held in memory or will it go missing on reboot?
Is there any way of knowing that the actual usage is valid and correct. Interim updates are UDP so is there a way to know that the Mikrotik wont duplicate data by resending historic values?

We have users that complain that we are billing them incorrectly and I would really like to get to the bottom of the issue.
I have setup up Netflow v9 to a server and I monitor traffic on the ports and the values on the netflow stats are always lower usages.