Why can’t my insurance company give me an estimate?

I’m trying to schedule a minor outpatient surgery with my doctor and I’d like to have an idea what this will cost in advance since I have a high deductible plan and still have ~$2,000 left before coinsurance kicks in.

My doctor’s office kindly provided me with the address of the place I’ll be having my surgery, the NPI of the physician that will be performing the surgery, and the relevant CPT codes of the surgery so that I could ask my insurance company what the allowable amount will be.

I have my insurance under Anthem Blue Cross Blue Shield and confirmed with their care-finder tool that the procedures are covered (10% coinsurance after I meet my deductible) and that both my doctor and the hospital where the surgery will be performed are in-network. All I need to know is how much this is going to contribute to my deductible.

I’ve talked to multiple representatives and they all claim that they can’t tell me what it will cost until it’s all said and done. They can’t even give me an estimate of the cost.

It seems wild to me that I won’t know how much I’ll need to pay until I get the bill. Is this really the case or have I just been speaking with really bad insurance reps? Any insights are appreciated!