Question about contractual completion

Would you accept the first paragraph as it is, or do you find it permissible?

§ 4 Completion

The seller commits to the full completion of the purchase object by no later than the end of July 2017. No claims can be derived from a delay of less than two months. Early completion by the seller is permitted.

The execution period is extended by the time during which the buyer is in arrears with the completion of own work or with due purchase price payments. Obstacles in the production of the object due to circumstances for which the seller is not responsible, e.g. force majeure, strike, lockout, transport blockade, bad weather days, soil findings during excavation work or subsequent special requests by the buyer, extend the production period by the duration of the obstacle.

What is your problem with the paragraph? There is a completion guarantee until the end of 09/2017.

Correct, but a delay of 2 months is acceptable according to the developer. Of course, we see that differently. That is two more months with a double burden.

why should that not be permissible? you do not have to accept the contract in that form.

Then find another provider. They may not write anything about a waiting period, but instead offer a fixed date directly - end of 09/2017.

Would you have preferred if he had stated Sept. from the beginning? That is not a dealbreaker for me. If the purchase price was agreed upon based on July, I would simply renegotiate.