Although it is clear how to use this in the description, the phrase "must match" has been bugging me.  It isn't strictly true since one can have 'all' on the database and 'fast' on the cursor.  It occurs a few times in other files like api_data.py too.  I haven't been able to think of a succinct suggestion.  "...must be less than or equal to the performance price of the database configuration"?  "...must not be more expensively configured than the database"?