You're quite right; the front pads do most of the work and wear out much faster than the rear ones. Also, as you're obviously aware, there is a very effective acoustic warning when the pads are approaching their wear limit. From your other post, I see that your car has never had any of its pads replaced, so it's highly unlikely that both front and rear pads are worn to the same degree. I would go so far as to say that the figure of 70% is something they've pretty much just plucked out of the air. So, ignore the avaricious screeching of the Honda dealer and wait for the much more helpful screeching of the wear indicator; then, go to a local independent garage with a good reputation and have the pads replaced for about half what Honda would charge.