When comparing a real trajectory and a computed trajectory there might be discrepancies due to parameter errors . This means that the conditions and parameters on which the calculation is based may deviate from the real-world conditions and parameters. Parameter errors can be reduced by proper measuring technique. A model error is the worst that can happen. EB is based on physical models.
Physical models are generally simplifications of the real world.
One restrictive assumption of all the models applied by EB is bullet stability over the whole trajectory. However, if a bullet is unstable, EB will produce false results, not because it is a bad software, but because the model assumptions are not fulfilled. It has been observed that bullets may be stable close to the muzzle and become unstable as they travel on. EB receives the date from the operating system. As long as the operating system gives the right date, EB will have the right date as well.