Tesco reported a bigger than expected hole in its accounts on Thursday after finding mistakes in booking income had gone back further than initially thought, forcing Britain’s biggest grocer to scrap its full-year profit outlook. Tesco, which has lost 20 percent of its market value this month after the accounting mis-statement compounded three earlier profit warnings, scrapped the outlook as its second-quarter underlying domestic sales fell 5.5 percent. Tesco shares dropped sharply at the open, down 4.5 percent in the first minutes of trading.