Hi. I installed nlbw yesterday, restarted the router and then downloaded about 50GBs of torrents.
To my surprise this is what nlbw is currently showing as data usage:
Details would matter here…
You don't tell us the device/ model in question, its configuration (offloading!) or just about anything (and even the OpenWrt version isn't that easy to read).
With hardware flow offloading enabled, the CPU does not see the offloaded packages (which is the entire point of flow offloading) and consequently will not be able to count them.