Extra 1c displayed on transaction

I entered a transaction with quantity and unit price and added a line to display rounding to what I paid in cash.


However, although the total price displayed correctly inside the transaction, it displayed as a cent more expensive in my cash transactions tab

This is because your currency, NZ$, is only divided into cents. Each line on the payment has to be rounded to the nearest cent, not the transaction as a whole. In the case you cite, two lines have fractional cents that will round up. Since this is a cash transaction, that means you had to have paid in actual dollars and cents, so you should enter amounts that produce a total in dollars and whole cents. Your rounding amount is fictional anyway, so adjust it so the total matches what you paid.