Although I know little about gambling, I believe the first throw of the dice, if it comes up 7 or 11, is a "winning toss."
If the dice do not add up to 7 or 11, subsequent throws must be made to win. The risk of loss increases/winning becomes more difficult.
It would be lucky to have a "winning toss" on your first and every turn. So, Gillnetter's explanation would also be correct.