Abstract: An electronic device for determining a level of toner volume in a replacement toner cartridge used in a printing device comprises a communication element, a memory element, and a processing element. The communication element transmits a request to the printing device to provide data regarding the replacement toner cartridge and receives the data. The data includes a current level of toner volume and a current printed page count. The memory element stores the data received from the printing device. The processing element is in communication with the communication element and the memory element. The processing element is configured to determine one of a plurality of sequential phases of a usage cycle of the replacement toner cartridge corresponding to a value of the current level of toner volume and determine a corrected level of toner volume using one of a plurality of equations selected according to the phase.