She was indeed, very likeable!
But dude! (or dudette...) one thing you should never say to the cashier:
"this is actually supposed to be doubling my coupons, I'm supposed to be making money on it"

What??
That manager must have been clenching his teeth as he approved the manual adjustment. Safeguards had obviously been programmed into the registers to prevent that kind of overage.
She walked out with $155.42 on her gift card! That's not paid by the manufacturer, it's a store's loss!
Be ready for some policy changes in the near future!