Inaccurate mobile traffic statistics

The mobile network traffic statistics that KWGT is reporting are very low.

My phone reports 2.69GB used since the beginning of the billing cycle.
3G Watchdog reports 2.51GB used.
My service provider reports 2.37GB used.
KWGT reports 1.43GB used.

KWGT is always low, no matter what time period I look at (e.g. since the 1st of this month, phone reports 413mb, 3G Watchdog reports 398mb, and KWGT reports 243mb).

I have a Samsung Galaxy 8 running Android 9.

From what I've gathered from searching is that KWGT doesn't track hotspot data usage.

Glasswire (data tracking app) shows 932.7 MB used this cycle, phone shows ~950 MB and KWGT shows 911.9 MB. Glasswire was installed 3 days after the cycle started, so that is probably why it shows a little less usage.

Glasswire also shows 35.2 MB under tethering. That would put the usage between KWGT and my phone stats pretty close.

I had found a post on Reddit (that I can't seem to find now) that said it wasn't a feature but the developer would look to add it in the future. I think the post was from a couple years ago though.

That may be, but I don't use hotspots. It's strictly mobile data.

This issue is still alive in v3.51b30911. It shows Today: 4.61mb, Yesterday: 3.39mb, Current month: 8.00mb. On the other hand, my provider in Serbia (mts) shows almost the same as Data Counter Widget app ... Today: 9.12mb, Yesterday: 10.43mb, Current month: 19.56mb.

Any thoughts?

edit: No hotspots or anything but pure mobile data was used. Huawei, Android v9

IMPORTANT: what I have just noted now, Data Counter widget and GlassWire (also accurate) apps require so called "Usage Information Access" setting enabled in phone system settings and both apps appear there; Kustom is not listed there on the other hand. Hmm...

And both working apps require Make and Manage Phone Calls phone permission too. This may be a lead to the solution

Yesterday kwgt said the correct amount.

Today kwgt is wrong.

No hotspot. No tether. Yes vpn for some of it.

Plz fix

Android 10 unihertz jelly 2

The issue is still present in v3.51b31415. As it hasn't been fixed for at least a year I'd rather ask a question - how to workaround it? Is there a system file with the traffic details, which could be read? Maybe tasker could help here?

Data usage is totally wrong when i use r0d for example.

Today

ts(mt, m, r0d)) give 950mb, totally wrong, i was only in wifi. So I use data. And I get 500mb ???

ts(mt, m, 1dr1d, 1dr0d)) give me the correct data usage, 7mb

So I change all my formula like that. And I get same data usage from phone traffic stat parameters page.