The following investigations were made in order to establish the accuracy of the Boltzmann code reported earlier: (1) test cases in order to determine the accuracy of the code when electron-electron and superelastic collisions are not included (the code predictions are compared with published results); (2) investigation of the effects of superelastic collisions (an example using krypton and krypton metastables is presented); and (3) investigation of the effects of electron-electron collisions (for this case also a typical example of krypton and krypton metastables is presented). In order to investigate the accuracy of the present code when electron-electron and superelastic collisions are neglected; two cases were investigated. The first case was that of argon and the second case was that of helium. The cross-sections and some experimental data for these gases are readily available from literature.