In May 2015, HP 364 XL printer cartridges cost 79.90 (+/- 5 centimes) each at Migros and Dipl. Ing. Fust, in April 2016 84.90 and in December 2016 already 89.90... Is this pricing and agreement with competitors related to the current weakness of the Swiss franc? Do I have to go all the way to the Migros company Digitec to pay just CHF 64?