System is allowing invoices to be written even though customer is over credit limit

We have tried:

Setup > Accounting > Accounting Preferences > General > Customer Credit Limit Handling

and selected includes orders.

Both of these options still allowed invoices to be written over the credit limit and only affected the overnight approval. The invoices were not automatically approved overnight and had to be manually approved in the morning.

If anyone knows the issue behind this, can you please advise?