Giveaway, the excess product being packed into orders, is one of the contributors of revenue loss that pre-packaged food manufacturers care the most. In collaboration with an egg packaging company, this study aims to discover operation rules to mitigate the giveaway in egg orders. For that, two variables have been raised as potential controllable factors of giveaway. One statistical model has been developed to better interpret the experimental results by understanding the underlying rules of the egg grading machine. The experiments have been accurately reproduced by a simulation using the estimated model parameters, which indicates the success of the model. Based on the experiments, we claim that the number of accepted downgrade grades has a significant influence on the final giveaway ratio. Limitations and further potentials of the statistical model have also been discussed.