If they are all set to auto, it will change automatically, but based on an algorithm, which means that it may not necessarily alter for every single change in value - eg if your total goes from 140 to 141, it's unlikely that the axis bounds will change. Looking at your images, I suspect you would be better off using a 100% stacked column chart so that it always occupies the entire axis in total, but that's a guess as you haven't really provided any context.