The problem with the Adsense responsive ad is it doesn't resize property as the screen size changes. What makes it usable is if you reach a page, the ad is shown correctly and that's way beyond what it was before.
If you'd like to test and see how the ad changes and adjusts to the screen you're welcome to check it on my site www.SEO-Company-Melbourne.com.au. First test the page on the desktop. As you narrow the page you'll notice the responsive ad from Google doesn't adjust property whereas the rest of the page does. If you press Refresh then the page will now display the ad in the correct size. I suspect most people simply browse and when they reach the page they'll see it correctly for the current size of their browser window. To me that's usable.
On a mobile device such as the iPhone if you flip from portrait to landscape you'll see the small size ad is kept. If you start in landscape and flip to portrait you'll see the ad is too wide. Press Refresh or reload and you'll see the ad is the correct size. Not perfect but again usable.
At last I feel we can probably use the Adsense responsive ad. The hope is Google continues to improve their code in the background so that later without us doing anything, and even unknown to us, the responsive ad starts to behaviour exactly as it should.
Call 0415 910 703 for IT support.