Why can you take 6X odds on some numbers at craps but not others at a 5X table?

Question: I played craps where the casino allowed five-times odds on the Pass line. On my first bet, the point was a six; I had $5 on the line and put down $25 odds. On my next bet, the point was a nine. I put down $25 odds but the dealer said it had to be an even amount – up to $30. The next shooter had a point of eight; I put down $30 odds and the same dealer said the maximum was $25. Needless to say, I was confused. What's the story?

Answer: Casinos only pay craps bets in whole dollars. The "flat" part of a wager on the pass line, the initial bet, pays 1-to-1. Put down any amount of whole dollars between the table limits and the house can match it. The "odds" portion pays in exact ratio to the chance against winning, so an adjustment is sometimes needed to permit payoff in whole dollars. Here's the situation with a $5 flat bet in a game with 5X odds.

On sixes and eights, chances against winning are 6-to-5. Any multiple of $5 up to the 5X maximum is acceptable as odds, and pays $6 for every $5; for instance, $25 odds pay $30. On fours and 10s, chances against winning are 2-to-1. Any amount up to the 5X maximum is acceptable as odds, and pays $2 for every $1; for instance, $25 odds pay $50.

On fives and nines, chances against winning are 3-to-2. Odds must be in $2 multiples – even amounts – and pay $3 for every $2; for instance, $10 odds pay $15. If 5X is an odd amount, you can "even the odds" by raising the bet. The casinos could hold you to one extra dollar to do so, although most houses let you go to 6X.