What should multi-year back tax filing cost?

Looking for a reality check on what I should expect to pay for a multi-year back tax situation. The IRS has sent me a notice listing missing returns for 2020-2024, and I also need 2019 and 2025 (extension) filed.

Here's the breakdown:

– 3 LLCs. One already has returns filed through 2024. The other two need returns filed for their active years, one active since 2019 and the other only about a year.

– 6 years of personal returns (federal + state, multi-state involved)

– Bookkeeping needs to be done from scratch for 2 of the 3 businesses. One only has bank/credit card statements, all other records were lost. The other has more records but inventory was never formally tracked.

– Entity restructuring (likely LLC to S-corp for the main business)

– Tax planning for 2025-2026

– IRS and state communication/representation

I've received a quote of $8,000 as a retainer deposit from a tax firm, billed hourly at $395/hr for EA/CPA work and $500/hr for tax attorney. The $8k is clearly just a starting point. Bookkeeping is being quoted separately and I haven't received that estimate yet.

For those who have dealt with or worked on similar situations, what did the total end up costing? Just trying to understand if I'm in the right ballpark or getting taken for a ride.

Not looking for solicitations, just ballpark ranges from experience. Thanks.