Final Loan Agreement - Which Time?

So, when it comes to collateral and such, we are actually quite conservative; nevertheless, we only finalized the financing months after signing the contract with the general contractor (GU). This was partly because the KfW expert from the GU did not want to be active before the signing, and without confirmation of the application (BZA) from him, the financing (with the KfW component) could not be secured. It was actually poorly managed by the GU, but oh well. However, we had several preliminary discussions with multiple banks and with about 40% equity capital we were/are very well positioned. Every advisor told us that it would basically not be a problem to complete financing. And we also had a good relationship of trust with the GU; of course, we had some planning meetings with him and he then—albeit only verbally—assured us that if something failed with the financing for unforeseeable reasons (accident, illness, disability, etc.), he would offer to exit the contract and only bill for what had been done up to that point. Of course, only during the planning phase. On the one hand, this reduces the risk of having to pay commitment interest. On the other hand, at least for me, there was the fear that the bank, knowing that we had already signed the GU contract, would worsen the conditions because we were basically under pressure. But that did not prove to be the case and everything went well. In the meantime, we have completed the financing, but construction has not yet started; however, this is due to other reasons for which neither the GU nor we are responsible... Ultimately, you have to feel good about your decision. If you want to avoid any risk, then you finance early and swallow the bitter pill that you may pay more. But at least that is manageable and you can sleep well.

We signed the loan agreement after we had obtained all the cost estimates and clarified that these were indeed fixed (all trades were from our small town). All cost estimates were adhered to except for minor additional costs because something extra still had to be adjusted. In the end, we had about 12% additional costs because during the construction we ended up choosing higher-priced materials and paved more than originally planned, built a larger garden house and roofed the carport with tiles from the roofer, more expensive masonry entrance gate, etc. But including the plot, we paid exactly (according to the Excel table) "only" €314,345 for 122 sqm and 680 sqm of land.