yuromastic
Though the following may not help to answer your specific question, it will show a breakdown of the charges on your bill, including the things that aren't included in the plan price.
If you sign into the HughesNet myAccount website, click on the "My Bill" tab, then click on either "View Current Invoice" on the upper/middle/left or click to view one of the past invoices toward the bottom of the page, the invoice will open in a popup. While in that popup, if you scroll all the way to the bottom and click on "View Site Details" on the left, it will give you a breakdown of each of the charges that make up your bill, including the plan fee, equipment lease fee (if the equipment was not purchased), any taxes and any discounts.
http://my.hughesnet.com/myaccount
If this doesn't help to answer your question, as in if it's a billing discrepancy type thing (like a difference in what you were quoted), the reps are on M-F from approximately 8AM to 5PM EST, and they are the ones who will do so. They normally reply to a new post within 48 hours.