I went to buy back one of my planes and noticedthat the 50% discount for the planes from tier 4-7 and the 30% discount for planes from tier 8-10 was not there, , which means that I need to pay full price for the pane even if we have a discount.
Screenshots link (because I didn't understand how to get images here):
https://imgur.com/a/Slb1aYp (this is an album whit 5 screen shots).