How does the scoring system work in leader board?



Can anyone help me to understand the scoring system in the competition? For my model I am getting different score but even though I did not change any hyperparameters! also when I have better RMSE and cv mean I am getting poor score in leader board than I have higher RMSE and cv mean in my model. So for hyperparameter tuning I checked solution every single time because my cv mean and RMSE did not make any sense when I saw I got poor score for better RMSE and cv mean. My final score is 1148.89 and position 247. Please share your thoughts so that I can understand the logic behind this. Thank you