Very good point Axl.
Indeed it is unclear as to whether one mistake in total can be made throughout the game, or one mistake per set of cars is allowed to be made. That is something that I know Bob would have made very clear, especially on a first playing.
This game is kind of a combination of Money Game and Penny Ante. Reminds me a bit of Temptation too as they display the guess on the game board before determining whether the guess made is right or wrong. I heard audience members applauding when the numbers were put up on the board. Clearly they assumed the player was right because the numbers were lit up on the board, but that clearly wasn't always the case in this game.
Overall a somewhat nice variation, and a pretty quick game at that. Nice to have a bit more variety and not so many appearances of Lucky Seven, Money Game and the dreadful That's Too Much! This game seems semi-winnable at least. If you goof on the first set of cars, you still have a 1 in 6 chance of winning. If you are right with the first set of cars, then it's a 2 out of 3 chance of winning.