- you are wrong here.
If you calculate your discount AFTER taxes they are paying 91.60€ for your product. and 17.40€ (19% of 91.60€) taxes. Together its the 109€ you already mentioned. - This is already planned for v1.6.0 (LINK, LINK2)
There will be an official answer from @Severenth @UnderDog and me in the next coming days.