Tricky Cash Registers Stealing Your Money Again?

Are you always looking carefully at your invoices and store receipts!  Watch the cashier’s monitor as they scan items. Statistically, i find they over charge more often than under charge! They call this “computer error”?  Well if that’s the case, then why do most stores lay out the pricing information in a confusing manner so you can’t as easily understand what they’re scanning? I kindly ask the cashier to explain the display, and they’re usually friendly about it as they do get others who have the courage to ask.