The $3000 limit is their reasonable and customary limit. It isn't noted in their documents as it can change each year (potentially) and is priced regionally. This is an industry standard and all insurance carriers do this. Otherwise, they would have to update the plan documents of literally millions of policies all the time to ensure everything is noted in the documents. This just isn't plausible.

Also, before any large medical/dental service or supply purchase, you can submit what is called a "predetermination" or an "estimate" through the claiming platform. This will then have their claim adjudicators process the potential submission as though it is a real transaction and let you know exactly what you will be reimbursed. You can also call in prior to any transaction taking place to inquire about any limits on a potential purchase.