Hi John,
It's a big jump in your mind but not in reality. C25K (as you would have noticed) increases the running intervals and reduces the amount of time you spend walking. I flipped it the other way.
Think of it another way. The difference between running 10 minutes, walking 90 seconds and then running 6 minutes is only 90 seconds of walking. The difference isn't 16 minutes of running.
Does that make sense? Hopefully so as it really helped me get my head around things.
I think the app I used was much more gentle in its progression.
Martin