In the end this is a 'how long is a piece of string' type of question as it would depend on so many factors that would be impossible to capture in a poll like this, including the procedure, the administrator, the specific option you are on,. In the optical industry any medial option that is part of the PPN capitation scheme, pays out rather quickly. Discovery and a few others have the ability to receive some claims directly and process them for payment, instantly, with payment then only subject to the normal batching and EFT delays.
Well I've only ever been on Discovery and they always pay out very quickly. One time I submitted a claim late in the evening and was paid out the morning afterwards. Was pleasantly surprised.
I never had an issue with Discovery paying out provided the claim was valid. It was just their support for a communist takeover of the entire medical system that put a bad taste in my mouth.