External construction supervisors Berlin / Brandenburg towards West

From my point of view, these are two separate issues, one of which is better handled by a lawyer, and for the other you need a technical expert. In postal code 15, well, I'll call into the thread for you ;-)

Builders' association. Had the construction service description and the contract checked there. Price is €2,900 including construction supervision (13 appointments).

How did you arrive at this price? On the website, I find 3 service packages. The cheapest, which "only" includes checking the contract, construction service description, etc., is priced at €2,250, the most expensive, which includes, among other things, 9 construction inspections, is €9,950. Am I looking at the "wrong" builders' association?

How did you arrive at this price? On the website, I find 3 service packages. The cheapest, which includes "only" checking the contract, construction performance description, etc., is priced at €2,250, the most expensive, which includes among other things 9 construction supervisions, at €9,950. Am I looking at the "wrong" builders' association?