NBC has ordered additional episodes of the game show "Deal or No Deal" three days into its five-night run. The Endemol USA show, hosted by Howie Mandel, is likely to return in March. The number of additional segments is yet to be determined. "Deal or No Deal," which challenges contestants to win a $1 million prize by guessing which of 26 sealed briefcases contains the largest cash cache, airs Monday-Friday this week. Since its premiere Monday, the show, based on a successful international format, has dominated the 8-9 p.m. hour in all major rating categories, growing consistently night to night and during each broadcast from 11.6 million viewers and a 3.9 rating/11 share on Monday to 14.1 million viewers and a 4.9/15 on Wednesday.