I saw your post on refilling 220/221 520/521 using the german method.
Have you ever tested how many page yields one can obtain from these carts ? If i'm not mistaken they are 19ml and 9ml and the printers they are used on cleans heads much more frequently then previous printers
To be honest: I do not have a 220/221 printer, since I did refill them for a friend of mine and since he and his familly not print as much, the cartridges will last for about 4-5 months. I tray to stay as long as possible from these ink gulping machines...