Is the KFW 153 confirmation mandatory after conducting the Blower Door Test?

Good day,

we had our KFW55 house built by a construction company. Now the house is completed except for the sealing in the ground-contacting part and a part of the wooden cladding.

Now our builder or his appointed energy efficiency expert has sent me the "confirmation after completion" with the request to sign it and forward it to my credit bank. But now the problem arises from my point of view. The energy efficiency expert was not on site to inspect the construction or to perform a Blower Door test. I assumed that the Blower Door test is mandatory. Is that not the case? If I now sign the "confirmation after completion," I may possibly have no opportunity to take action against construction defects afterwards, or how is that? Since the entire construction has been delayed to now 1.5 years due to Corona, I must slowly but surely give the confirmation, otherwise the "subsidy" will be withdrawn. Maybe someone has a tip on how I should proceed. Many thanks in advance.

Regards

I just read that without a ventilation system, no test is apparently necessary. It says so in the attachment to the information sheet of the 153. I cannot say anything about the other questions.

Ah. A test is probably necessary after all, but the result doesn't matter... somehow...

Okay, I also have a ventilation system in the house. Unfortunately, I didn't find anything about the Blower Door Test in the leaflet for the 153. Could you maybe tell me where you read something about it?

It is stated in the "Anlage zum Merkblatt" under "Formulare und Downloads" on the information page for the 153er.

Now our construction contractor or rather his appointed energy efficiency expert has sent me the "confirmation after execution"
with the request to sign it and forward it to my credit bank.

What kind of document is this?
Is the blower door test included in your construction contract? By now, the contractors no longer pay for it, but it should be included in your construction specifications.
The BDT is mandatory for the KFW. As far as I know.