Extreme increase in data usage

I have had a ton of issues with Data usage, but I haven't found cox at fault.  I have the 1TB + 500GB because I have 3 teenagers in the house that play games on the PC.  What I found was that in some months those games would all have huge updates, like 50GB which would hit all three PCs, so 150GB of usage for just one game.  the Second issue was kids leaving the streams running.  They might log into twitch or something and have that just running in the background while the PC is open.  Usually with full stream, you are talking like 500Kbit per stream times 3600seconds times n hours.  it adds up fast.  Finally the same issue happens when you have a fire stick or other stream stick, they can sometimes keep running even after the TV is turned off.  That, again, can eat up usage.  

My personal solution was to get a router that supports Gargoyle (a version of openWRT:  https://www.gargoyle-router.com/) It allows for FULL visibility and control of your network usage.  Using this, I can track the EXACT amount of data crossing the network and actually pin down who is using the most data.  With this, you can lock out anyone you don't want in the network and you can restrict bandwidth through quotas.  So, for example, this month we are close to hitting the cap....like 40GB away.  So I turned on restrictions.  After 10GB of usage (each day) the available total bandwidth drop to 1Mbit.  Still usable, but harder to share.  After the billing cycle, I just open it back up again.  I've found that Cox is within about 10% of the number that I get from the router.  It's really close.

I can also restrict time of day usage by mac address, so the kids are locked out until certain hours.  It takes a little work, but functionally i like the results.