Financial Settings / General Settings / Price Lists, Fees & Taxes / Price List Configuration / Get Pricing Category from associated Group when Subject Pricing Category is none (null)
Here, you specify if the pricing category of the subject will be inherited from the group when the subject category is not selected.
Example
Setting -> Active
The following pricing categories are inherited from the Year 6 Blue group (Figure 1)
Figure 1
Setting -> Inactive
When the setting is inactive, then the pricing categories have no categories selected (Figure 2)
Figure 2