Asuswrt-Merlin: 3G modem traffic not counting..

[drummah]

Hello!

I got Firmware:3.0.0.4.374.32 (Merlin build) installed on my RT-N16
Using USB 3G/4G modem plugged into router. (Huawei E-372).

Everything works fine, but traffic counter do not counting any internet traffic...

That's quite usable feature, since my 3G traffic is limited to 50Gb per month,
so I cant see when I'm going out of it...

Any suggestions? some sort of script or anything that i can install to N16?

thanks!