To confirm the actual ink remaining, visually check the ink levels in all of the printer's tanks.
If any of the ink tanks are not filled up to the lower line, fill them to the upper line on the ink tank. Prolonged use of the printer when the ink level is below the lower line on the tanks could damage the printer.
You can check the approximate ink levels from the computer, and the approximate service life of the maintenance box from the control panel or the computer.