Navi theft – Does insurance pay MwST despite a small amount?

Hello together, short information in advance: theft of screen, head unit + operating unit from my BMW 1 on 02.02. I immediately reported it to the insurance company. On the same day, the expert was also the workshop where the car is repaired. Pure repair costs incl. operating unit: approx. 900€ HUK then sent me an expert report for screen + head unit: 3.060€ I have already received the 3.060€. I asked extra: The money is only for the new procurement The repair is completely billed by the dealer with the HUK. Car has been in the workshop since Monday. Yesterday the information is received that 2 cables have to be moved through the interior to the Koferraum. So assume that the 900€ does not get there. Question 1) Pays the HUK because now 900€ according to KVA and the rest I have to pay, or the HUK pays the amount that is on the invoice at the end (say 1.400€) Question 2) I have the screen and headunit from e in a certified dealer used to buy for 1.920€. So much less paid than I got. Is the problem if I submit the invoice? Question 3) At that time on the phone I asked for MwST refund. There I was told that I only get the MwST refund for the repair invoice, but not for the display/headunit invoice. Is that right? Greeting