Your place bets are normally off on the come out roll, but with a come bet, the rules are slightly different. You can't turn your come bet off, but you can take down the odds. If you aren't feeling it, or just want to be done with the roll, the dealer can take down your bets. The other difference is you can turn off your place bets. You can always place number and have come bets, always have come bets going, or place all the numbers. You made $15, but it took you two rolls to get there. So it comes down and you get your $10 back plus $15 dollars. You get paid $5 for the come bet and the odds gets you $10 (pays 2:1).
You put $5 in odds (so now we have $10 on the 4, just as we did with the place bet. Now you can keep the $18, or you can press your bet to $15 or $20 or more. You placed the bet once, it paid off once. If it hits, you get paid $18 ($5 pays 9). Placing numbers and come bets are different playstyles.
