Yes that is normal. I have a Surface 3. All Surface devices have this, even the Windows RT ones. Can you do me a favour? I recently clean installed my Surface 3 with Windows 10 and there seems to be some doubt as to whether the Threshold Update 2 version is working properly with hardware drive encryption. Please can you launch PowerShell as Administrator and post your output of the following command:
PS C:\Windows\system32> manage-bde -status
BitLocker Drive Encryption: Configuration Tool version 10.0.10011
Copyright (C) 2013 Microsoft Corporation. All rights reserved.
Disk volumes that can be protected with
BitLocker Drive Encryption:
Volume C: 
Size: 115.93 GB
BitLocker Version: 2.0
Conversion Status: Used Space Only Encrypted
Percentage Encrypted: 100.0%
Encryption Method: XTS-AES 128
Protection Status: Protection On
Lock Status: Unlocked
Identification Field: Unknown
There is some suggestion that the Encryption Method should say "Hardware". What does it say on yours?