Data usage meter totally wonky last two weeks

I have noticed over the last two weeks, my data usage has been ridiculously wrong. I generally use 1-3 GB a day, a little more on days that I stream. For the last couple weeks it has been saying that I am using only 100-200 MB a day (the traffic meter on my router says I am still using 1-3 GB a day). Oddly, the days I restart my router due to wifi issues (when I restart my router, I generally restart my modem as well), I get more accurate data meter values.

Its not charging me data, so I am happy, but if it can undercharge me, it can possibly over charge me in the future...