OpenAI had previously tried out completely hiding this monthly limit option from pre-paying users. Stupidly, as then for those that had set a limit, it still was working, and couldn’t be changed. That was shortly fixed after a day of cutting off developers.
And then after a week of screaming, they put it back.
Could it be that the option is still made useless to stop usage over the setting?
The expected delay would likely be similar to the propagation delay in an API being disabled after use - sometimes minutes, sometimes much longer.
The largest fault in any delay at all is in outsourcing not just the payment collections, but the very accounting of every API call, to CEO buddy buddy Stripe.
Since there is no OpenAI advocate actively engaging here, the place would be API->Feedback in the help option of the API platform account.