Why on Earth could they possibly feel it necessary to do this? The United States Patent Office doesn't have a complex system of sub-domains or even an EV license, if money were the object then they could just go with Let's Encrypt (not to mention the current license continues until 2018 anyway).
The amount of computing power it takes to encrypt with SSL is minimal, especially if you use some of the newer systems like ECDSA and should not be of concern to a company like the Patent Office.
The amount of computing power it takes to encrypt with SSL is minimal, especially if you use some of the newer systems like ECDSA and should not be of concern to a company like the Patent Office.