“ There are chips inside the original cartridges to record how many pages were printed and they cannot be reset. As a result the printer reads the chips and tells you that the cartridges are empty, even though they are not. This is why you are getting the "ink low" message even though the ink tank is at full capacity.”
This is the same with every single refill not just mine. If more reassurance is needed that I do not send out part filled cartridges please go to Inksupport.info which is a Tesco inspired site that explains this. Empty HP weigh 23-25gm so if you weigh them every gram is a millilitre of ink.
If you want the the ink levels to show accuracy you have to buy original cartridges from HP…hope this helps.