@davidvperdue 

You can sign into the HughesNet MyAccount site, hover over My Account and click on My Bill.  On that page you can look at current and prior invoices, including a breakdown of each invoice to see what the higher charge was for.  To see the further breakdown, scroll down and click on the blue links while viewing a particular invoice. 

Perhaps a discount ended or there was an extra tax.  Some jurisdictions have a tax that is applied once a year.