If you've ever tried to change the spot count of a class and found your edits were not saved, you've probably run into the Spot Count Hierarchy. Simply put, there are 3 places where the spot count is set (starting from the bottom of the hierarchy):
In the settings for the specific class (Scheduler)
In the settings for the Class Type (Admin->Scheduling/Retail->Classes)
In the settings for the Room (Admin->Configuration->Rooms)
These three settings are linked in a very specific way. The Room spot count or the Max Spot Count is the default spot count for a Class Type in that particular room. The Class Type spot count is the default spot count for a Class of that particular type.
You can easily decrease the size of a single class or the size of a Class Type in a particular room. However, you might not be able to increase the size of either of these. The reason for this is the hierarchy, which looks like this:
Class Spot Count ≤ Class Type Spot Count ≤ Room Spot Count
The class spot count can't be greater than the class type spot count for the room the class is in. Also, the class type spot count in a particular room can't be greater than the max spot count of the room. If you try to increase the count past the count of the next level in the hierarchy, the change will not save. You will be stuck that the count of the next level.
Therefore, if you want to increase the spot count past the count of the higher level in the hierarchy, you will need to increase the count in the higher level as well. Here are a couple of examples to illustrate this idea:
Example 1:
Say the room size is 20 and you have a class Type that utilizes only 10 of those spots. You are going to do a special class of that type with 15 people. Increasing that single class size will not work, because the Class Type is capped at 10. You will need to change the Class Type count to 15. Then the class size will increase to 15.
Example 2:
Let's use the same room of 20 spots and Class Type of 10, but this time you want to increase a sing class size to 30. You won't be able to just increase the Class Type count to 30 because it would be greater than the max spot count of the room. If this scenario, we'd have to increase the room spot count to 30. Then increase the Class Type count to 30 and finally the classes count.