Let’s say two people will share 17,28 ticket. First one will pay 7,28 and the other one will pay 10.
If first customer that will pay 7,28 gives $10 you can type
7,28 + Split + 10 buttons and see the Change Amount.
Typing next amount, clicking
[All] button will hide change amount display and you can continue operation. For example clicking
[All] + Credit Card buttons at that point means remaining amount paid with CC.