Updating Available Column when move from waiting list to register is triggered

I am trying to explain to my clients how the waiting list feature works when a registration is cancelled, and I am a little confused myself.
Note: These are free events.

Example: 
Capacity is 60
There are 60 registrations and 10 on a waiting list.

Case 1:
One person cancels. There is now "Available 1" 
Someone comes to the website, see this and registers. She gets in. No one on the waiting list is moved.
Why does that happen?

Case 2
Admin cancels two registrations. It says "Available 2". She goes to two records from the waiting list and changes the status from Waiting List to Registered. 
The Advanced Registration Management page now shows 60 people registered and there are 60 names on that list. But the public list still shows Available 2 and the public list only shows 58 names. 
How soon will the public list update? Can someone still register and take it over capacity?

Update:
On the event that had 2 available (even though the advanced registrants list has 60 names) two more people registered because it let them. There are now actually 62 registered. So even though the backend suggests that capacity is reached, the public view allowed them to register.
 

For this, maybe should enable and use the plugin eventbookingdoc.joomservices.com/plugins/move-registrants

That should address your concern

Tuan

It was alreadt enabled, and works most of the time.

But I figured out what the problem was. With a group of two people, there are three records, right? They were changing the registration status for the individuals, but not the group. Once they did that, it worked out.

Hello

You are right. For a group registration for N members, there would be N + 1 registration records (N records for group members and 1 record for group billing)

If you change status of the registration, better changing status of the billing records instead of the group members record

Tuan