When your wife filled up, the attendant probably stopped the first time the pump clicked off. There may have been room for some more gas. The fill tube was probably empty and your wife drove home, you drove to the gas station using some gas. The second fill up took up every bit of excess space and likely filled the tube (from the gas cap to the tank) There is potential damage to the evap recovery system as liquid gas may have gone into the vapor recovery tubes. Older cars were easily damaged by overfilling, newer cars can still be damaged but are a little more forgiving. Drive the car to use up the gas to get it out of the fill tube and hope the evap system did not get messed up. You will get a check engine light if it does have liquid in it. If you are lucky it will clear itself, if not your local mechanic can fix this for you, $$.