Window offer evaluation - Is it okay like this?

Hello dear all,

we have obtained quotes for windows and blinds for our extension.
Could you please give me your opinion/assessment on whether the price of the following offer seems appropriate from your point of view?
I am convinced about the quality of the execution by the window manufacturer so far.
My concern is only whether I can or should accept the offer regarding the estimated price.
Thank you very much for your help.
Best regards,
Melanie

Here is the offer.

Is that with installation? The windows are already okay.. the blinds are a bit tricky..

First of all, many thanks for the quick feedback.
Assembly costs amount to 900 euros according to the offer.

Right, it’s at the very end. Just for comparison: I installed my own blinds, it’s not particularly difficult. For the dimensions of the large blinds, the factory charges 800€ gross, so they add 1200€ on top... The installation for 2 experienced fitters certainly doesn’t take more than 2 hours.

How do you arrive at a surcharge of 1,200? I think I can no longer do math. :-(