Cannot Change the Price Level Amount on the Item Record

On the Item Record > Sales/Pricing tab > user cannot change the amount on any price level. Each time a user tries to change the amount, it returns to the original value.
 

The user cannot change the price level amount if there is a discount rate entered for the price level. To check this, the user may go to List > Accounting > Quantity Pricing Schedules > click Edit beside the Quantity Pricing Schedule used for the item. You will see that there is a discount rate entered on the Qty column. To be able to change the amount of the price level in the item record, you will need to remove the discount rate.