The Texas Lottery Commission approved guaranteed Lotto Texas jackpots Monday, a measure designed to win back player confidence and avoid more inflated prize estimates by the nation's third-largest lottery.

The lottery was rocked this summer by revelations that former Executive Director Reagan Greer signed off on advertising jackpots that were higher than ticket sales could support. Greer resigned in July after Commissioner Tom Clowe told legislators that he thought the executive director had deceived the public.

As expected, the commission approved the guaranteed jackpot measure by a 2-0 vote Monday.

The measure means grand prize winners will be paid either the advertised jackpot or the jackpot based on sales, whichever is greater.

The Lotto Texas jackpot starts at $4 million and traditionally grows by at least $1 million each time no tickets match all five numbers and a bonus ball.

Under the old rule, the commission could use its reserve fund to pay a grand prize winner if it hadn't sold enough tickets to cover the jackpot during the first four drawings. But ticket sales usually are slow until the jackpot reaches $9 million.

The new rule, which will take effect late this month, requires lottery officials to make a "fair and reasonable" estimation of potential jackpots. If ticket sales fall short, the lottery would be allowed to pull money from other lottery funds to cover the difference.

Since the inflation came to light, officials have been holding the advertised jackpot at the same amount for several drawings until enough tickets are sold to warrant increasing it.

Another major Lotto Texas changes discussed Monday involve the field of numbers from which players choose.

Currently, players can win the Lotto Texas jackpot by matching five numbers between 1 and 44 and one bonus ball number from 1 to 44. Lottery staff members suggested having players select six numbers between 1 and 54 with no bonus ball — the way the game was played before the bonus ball was added in 2003.