I want to suggest to include in this app features the variable discounts for an specific items. I am aware that it can give discounts by percentage and variable, but when you give discounts on variables all items inside one ticket will get the discount. I suggest if their is a feature that only an specific item from one ticket can be given a discount. Regarding the percentage discounts, i am also aware that you can choose which item will be give discounts, but the down side is, you can only choose one percentage discounts. for examples you have 3 items in a ticket. Item one can get 3% discount

Maybe you can include access control on employees in accessing items category.