Costs for work planning are reasonable

A bank should not care about that

But usually it is for them. The problem passes on to the bank if first the general contractor and then the customer become insolvent.

There are supposed to be banks that release money step by step, where the payment schedule is quite relevant. The purpose of a payment schedule is to represent the principle of "simultaneous exchange." Ideally, after each stage, neither party to the contract should be at a disadvantage. A "surgically precise" line would be a doctoral thesis in itself in each individual case; therefore, it is always appropriate to handle it "flat-rate" and with "rounded" percentage values. But 50% for no more than just the pure starting signal reeks of an undercapitalized contractor.

But it usually isn’t for you.

That is exactly why the equity is required by the banks in advance. Then the bank also has no problem with such a payment plan.

That's exactly why the equity is required by the banks in advance. Then the bank has no problem with such a payment plan.

...if there is that much equity...

And of course the bank has a problem if already 50% has been paid but only 20% of the construction is completed in case of the insolvency of the builder. There are certainly banks that do not go along with that.

So I only understand the payment plan concerning the additional charges. The entire house will have its own payment plan, which is why there is no simple reference here, but a new one will be created.

So I only understand the payment plan concerning the surcharges. The entire house will have its own payment plan, which is why it is not simply referred to here, but a new one is created.

That may of course be the case, but it doesn't change the fact that it is quite cheeky. You have paid 90% of it and only about 10% of the work is actually completed. The rest only concerns the upper floor and above.