I have purchased a new Epson WF-7720 printer and after the trial black cartridge ran out I installed a new XL black cartridge. Trouble is that after less than 500 pages printing out, the status screen is showing that the black ink is almost empty. I am printing on standard print settings. XL is supposed to allow around 2,200 pages of print. What gives? Will return if XL only prints 500 pages as I cannot afford the ink at that point.