Very interesting. We are running a Mac OS X with Yosemite, and an Epson printer. Cartridges are very expensive - I've been ripped off here in The USA by refilling through Office Max, a chain of Office Supply. Did not FILL! Used to have a PC some years ago and I refilled the carts myself - messy ,but cheap. Sounds like you have a very good deal.
Looking into a thermal Printer, but the initial expense + paper is pricey - I don't understand the savings, As well, I want one that will print postage labels from any site, and am still researching. [sigh]. Ink prices stink. I wonder about getting German cartridges similar to yours for my Epson. Do you have a link, or is it a local purchase for you?
Thanks.