[DrBob]

I think you're mixing up calling a raise, and betting. Your calculations are the kind that's appropriate for calling. When betting (not counting a bluff to induce a fold) it's more appropriate the view only the odds on the NEW money that goes into the pot. So the odds here are the money put in THIS ROUND, from when you bet/raise, by others, to the money you put in yourself. This can only be estimated, but will never be more than the number-of-opponents to 1. Clearly much less than gutshot odds here.