You may be able to be put on invoice billing if you call and ask them. Conversely, you can start a new post in this section (myAccount and Billing) asking for the same. Keep in mind that there is a $5 per month invoice billing fee.
I signed up with HughesNet in Dec 2004, and invoice billing was an option given when signing up back then.
With regard to seeing the breakdown of your invoice, you can sign in at the HughesNet MyAccount site, click on the "My Bill" tab, and view current or past invoices. When viewing an invoice in the popup window, you can see a complete breakdown of it by scrolling to the bottom of the invoice and clicking on "View Site Details" on the bottom left. This view will give you every aspect of your invoice. You can then see what part has increased in price by comparing a current and past invoice.
Also, I believe that the two year commitment is noted in the script that they read towards the end of your sales call that they ask if you agree to.