Cost estimate and final invoice

Offer 200 sqm at €10 = €2000
Renegotiation 20% more
Invoice from the company after measurement 184 sqm at €13.00 = €2392
My calculation:
183 x 10 = €1830 + 10% = €2196

My calculation: 183x10*1.20 = 2196. Your 10% must be mistyped.

By the way, an invoice may deviate up to 15% from the offer, so the upper limit would be 2196*1.15 = 2525.4.

Could you please quote the section of the contract that includes the 19% price increase?

Ah, it was just a typo the 10%

No purchase price, but construction service
In the offer from May 2018, the estimated square meters of scaffolding etc. are listed. For the items, the individual prices and at the end the calculated final price.
10 days later contract negotiation with agreement of 19%. Negotiation protocols with new final amount
Sept. 2018 another 5%
Dec. 2018 contract with the LV from May 2018. But agreed sum now 24% more. The LV with the old sums is part of the contract, only the final price has increased.
This is okay so far. It was signed like that.

There are fewer sqm and meters according to the survey. And some items would not be charged because they were also not executed.

Be concrete for once:

- What is the total amount of items that were no longer delivered (0m, 0m², etc.) but still appear on the invoice? With how many sqm do they then appear?
- What is the difference sum of all items over 24% compared to the 24% limit? The 24% refers to the unit price (per m, per m²), not the total amount in the offer.

I believe the offers were net prices. +19% VAT after the homeowners' association was quite surprised, the engineer said: well, those were the price increases of recent years..