That is a high cost for an extra 5GB per month. It sounds like you might be on the same plan I am, and the only higher plan available is the one for $129.99. Quite a leap in price for not much extra allowance, though the speed is a higher up to rate.
You may already know this, but there are a lot of things you can adjust so that you don't go through a lot of data. Of course, if your reason for wanting to upgrade is to be able to watch on demand films and TV shows and such, all the adjustments in the world aren't going to help with that, save for watching said films/shows in SD.
My 15/50GB plan is actually overkill for me. I chose that only because I figured I would need it, plus I got $10 off per month for a year. As it turns out, I would be fine with the 10/50GB plan, and could actually squeak by with the 5/50GB plan, if I needed to. I just make sure nothing is automated that doesn't have to be, and I don't use the cloud or syncing. Also, this is with three PCs running Windows 10.
I hope you can adjust your computer(s) to be able to fit your existing plan.
Eek! Cut that cable! LOL. DirecTV will for sure eat through your data like there's no tomorrow.
I had connected my DirecTV to Hughesnet last year when I had my old legacy Pro plan. I just wanted to see if it would connect with wifi. Well, when I did so, it changed a lot of things on my DTV receiver, as it now thought I could use the internet for it all the time. I was able to disconnect it from wifi, so to speak, but the changes that had taken place didn't revert to what they had been pre wifi. To make a long story short, I ended up having to do a factory reset to get it back to normal. I lost everything on my DVR. Two reps couldn't help me to figure out what to do, and I had to figure out the factory reset on my own. Even though I lost everything, it was worth getting it back to normal.
If you have Windows 10 on the computers, you will want to make sure that they aren't using the cloud (OneDrive) and aren't syncing. To turn syncing off go to settings, accounts, then "sync your settings." The top option on that page should be to turn your sync settings on or off. Turn it off. As for the cloud (OneDrive), it may be on in your system tray. Right click it and go into the settings (I forget exactly what it says) and change it so it doesn't start on startup. I can't remember if there's anything else to change on it, but check anyway. Then exit out of it to turn it off for that time. It won't start again when your computer starts next time. The last thing with regard to the cloud is to go into settings, system, then storage. Make sure all of the save locations are somewhere on your computer, whether "This PC" or your C drive. Just make sure none of them say anything about the cloud.
Also, go into settings, then Update & Security. Click on Advanced Options, then Choose how updates are delivered. Turn off "updates from more than one place." That's another thing that will eat up some bandwidth.
Then make sure Facebook isn't set to play videos automatically.
Those few things alone will probably save you a lot of bandwidth.