Setting "spell_book_binding_level_requirement" and "spell_book_binding_level_cost" to anything other than default values has no affect even after game restart.
There is no issue other than the name of the config being slightly misleading.
These define the cost of spell book creation, not spell assignment to spell books.
Setting
"spell_book_binding_level_requirement"
and"spell_book_binding_level_cost"
to anything other than default values has no affect even after game restart.