Should one use nlbwmon if it's got issues tracking ipv6 and anything that bypasses conntrack?

Dear friends,

I'm trying to find a way to monitor my bandwidth usage. Someone suggested nlbwmon. However, several people have have mentioned that nlbwmon has issues tracking ipv6.

The creator himself, @jow, wrote this:

Anything that bypasses conntrack (NOTRACK rules, fastpath, hardware NAT accelleration) will lead to skewed results.

Is there a way to block/stop everything that bypasses conntrack? And would such a blockage/stoppage still let me surf the internet in a normal way?

To reiterate, I just want accurate results. I don't mind if the results are a bit off (something like +/- 1MB for every 100 MB). I'm also not restricting myself to nlbwmon. If there's a better solution, I'm open to hearing about it. But if nlbwon can be fixed to make it accurate in monitoring bandwidth usage, I'd love to hear that too.

Thank you for helping a regular, non-tech person.

I'm erring on the side of caution and accounting for my bandwidth usage based off Luci's vnstat info. I realize that it also includes "local talk", but I don't mind paying for that.

Fri Sep 1 23:01:41 PDT 2017 update: I'm assuming that vnstat takes into account "things that bypass conntrack (NOTRACK rules, fastpath, hardware NAT accelleration), yes?