I thought so too... Increase the price by 20Fr to then give a 15% discount, hahah
Nevertheless, the 15% brings the final price to 271.15 Fr. So far they have never been cheaper than 299 Fr. After all, almost 20 francs discount ^^

254.15 CHF was trzdm the better price.
(Monday's price 299.- CHF, minus the 15% discount, which was also offered on Monday).
The price development function would at least have made this transparent.