I don’t see any 3rd party inks on the inkjetart.com site ... so I assume you are referring to original epson cartridges.
Did you wait until the printer stopped and prompted you to replace in ink cartridge or did you replace it because it said it was low? It will say 0% or 1% well before it is empty, normally with 10% to 15% left in the tank. But you can keep printing until the printer literally stops and makes you replace the ink cartridge. I think Epson did this intentionally so fewer customers get caught without a spare.
from the manual ...
When the red Ink Check light is flashing and INK LOW appears on the LCD screen, the indicated cartridge is almost expended. Make sure you have a replacement cartridge. When the light stays on and REPLACE INK CARTRIDGE is displayed, the cartridge is expended. You must replace the cartridge before you can continue printing.