Do I have to pay for Unity multiplayer if I'm just using 20 CCU?

I want to use the Unity Matchmaking system. With the default Unity Account I can use up to twenty users for free. Does this also includes traffic?
So my game won’t be published so can I use the Unity Multiplayer Service without any costs (As long I have less than 20 ccu)?

20 ccu are free to use on the personal edition.
Only what exceeds that user limit generates traffic that will cost you.

So I won’t have any costs for traffic etc. as long as I stay under the 20 free ccu?

From the way information is put on Unity’s multiplayer services page, the limit for CCUs for each edition like 20 for Personal edition seems to be for development stage only. When you release your game, you have to pay for traffic that use Unity Matchmaker and Relay servers. Also if you use their Advanced Billing Calculator present on the same page with a CCU value less than 20, it still shows you a monthly cost. Which means calculator does not take into account the free CCU limits, indicating these CCU limits to be for development time only.

Also note the question below from their FAQs section on same page.

What do I need for my Multiplayer game to be “Ready to Release”? A
Unity Plus or Pro account, associated
with a valid payment instrument. Unity
Personal users can be granted an
excep-tion. For details, see this
forum thread.

which means you won’t be able to publish with your personal edition without Unity allowing you to do it. Now consider the fact that, if they are not going to get any earnings from your game, why would they allow you to activate your multiplayer feature in release.