The reason you might see a difference between the CCV number and the number of people in the viewer list is a variety of factors...
View count is the number of people who have the stream playing. That means they have you playing in a web browser, or they have your stream playing on Mobile, or a TV app, etc.
The viewer list is the number of people connected to the chat. That can mean they are watching on web browser, mobile or TV, but it can also mean they just have the chat popped out (not watching, but they can still chat). Another example is Chatterino or Chatty, third-party programs that allow you to connect to chat BUT you're not watching the stream.
And third, and I suspect this is the biggest problem right now... people think they can open 10 tabs and count as a viewer in 10 streams. They do not. They count in 2 streams, maybe 3. But that's it. And when you have more than 2-3 streams open, weird things happen with tracking. So they can be actively watching your stream AND chatting but they wouldn't count as a viewer because they count in a different player. (This is a common outcome with tools like the Twitch Lurker extension.)