It's easy to use up 200 GB in 6 days if you're doing activities that use up your data. HN doesn't use it for you; you do. And there are no caps. You continue to have data when you have used up the package you bought, just at a slower speed. Once you use up the priority data package, the Fair Access Policy kicks in, and you have unlimited data, only at a slower speed.
All spelled out here: https://legal.hughesnet.com/node/786
All Service Plans feature Priority Data and unlimited Standard Data. Each Hughesnet service plan (“Service Plan”) comes with an amount of Priority Data that may be downloaded or uploaded at Service Plan speeds within a billing cycle (“Priority Data”).
If a subscriber uses all of their Priority Data during a billing cycle, he or she can continue using the Service using unlimited Standard Data until their Priority Data resets. Standard Data is prioritized behind Priority Data, which means that during high traffic periods, subscribers using Standard Data may experience slower speeds, which will lead to web sites responding and loading more slowly and certain activities such as video streaming or large downloads/uploads being significantly impacted.