When a multiple and a maximum are set in the default order settings for an item, for example a maximum sales order quantity of 50 and a multiple of 5, then there is a issue when entering a quantity of for example 60 on a sales order line.
Error message:
The message "The order quantity must be a multiple of 5. Do you want to round up the order quantity to 55" will show when entering a quantity of 60. 60 is a multiple of 5, so we would not expect to get this question at all