I have no idea why any tech would tell you to avoid Glasswire. I can't fathom it. Perhaps that particular tech is averse to using anything free. I use Glasswire, as do a ton of people on here, including many of the Champions. Glasswire won't do anything to your system other than monitor it. It does to your system exactly what you want it to do.
The free version of Glasswire is fine. Glasswire does have it's limitations, as in it can only monitor the device it's installed on, but it's still a great tool. It would be able to show you exactly the info you are looking for, in that you can narrow the graph down to one hour.
Also, I noticed some discussion below regarding DirecTV. The bottom line is this...Hughesnet and DirecTV do not play well together. Even when not watching anything on demand, your DirecTV receiver will continue to use data, and sometimes a LOT of it. It will update the guide, program descriptions, and even download films that you never asked it to. Having DirecTV connected to Hughesnet is a really bad idea. Even when your DirecTV receiver is turned off it will continue to use your data because it's actually in standby mode, not really off.
I would not doubt at all that your DirecTV receiver is where your data usage problem lies.
To paraphrase Frankenstein's monster on SNL: Glasswire good. DirecTV bad.
If you have a Smart TV, using that for Netflix and such will not use more data than the streaming itself (save for an occasional, small firmware or app update).