Repair costs vs Wdw in case of further use or replacement

Hello dear community, there are a few questions in my mind at the moment. Let’s assume that there is a comprehensive damage with the following figures: replacement value 1500€ residual value 1000€ repair costs net 850€ The repair will be done in-house or abroad and later certified by the expert. Therefore, if the repair costs were to be net, the car should still be kept for 6 months. What would look like if one would have an equivalent value during these 6 months buy high-quality cars with excellent VAT? Does this still fit or do you have to be satisfied with the billing Wdw-Rw? I thank you in advance!