The A-V formulation based iterative algorithm method (IAM), developed at Paul Scherrer Institute, shows excellent performance in modeling the critical state magnetization-current in the ReBCO tape stacks after field-cooling magnetization. This article upgrades the function of the IAM, making it realistic to take into account the widely used E-J power law, as well as to model the magnetization-current in bulk high-temperature superconductors under a zero-field-cooling cycle, having both the magnetization and demagnetization stages. The simulation results obtained from the ANSYS-IAM are validated with the well-known H-formulation method for both the critical state model and the flux creep model. The computation times from using the two different numerical methods are compared and discussed. The influence factors, including the iteration steps, the initial superconductor resistivity, the ramping time, and the reservation coefficient, are studied in detail.