> The result is that instead of spending X units of time on spec and THEN y units of time on coding, you get the whole thing in x units of time AND you have a spec.

It's more like x units of time thinking and y units of times coding, whereas I see people spend x/2 thinking, x typing the specs, y correcting the specs, and y giving up and correcting the code.

Sure! That's inefficient. I know just how I work and I've been writing the type of programs I do for quite many years. And I know what would take me normally a week takes me few days at best.