@slth:
This might be a stupid question, but as the bug if ipfw related ("ipfw entrystats is returning wrong values, leading RADIUS accounting to have values considerably higher than reality."), does this mean every bandwidth monitoring package mentioned at http://doc.pfsense.org/index.php/How_can_I_monitor_bandwidth_usage%3F has the same problem?
No, none of those use ipfw entrystats. ipfw isn't even loaded unless you're running CP.