Maybe its a placebo, because the matter of fact is, faster charger did not start until the iPhone 6/6Plus. Maybe it took 5.5W instead of 5W, but the devices were not capable of taking 8W, 9W, 10W+. As mentioned your iPhone 6 would charge faster, not your iPhone 5. The iPhone 6 has a larger battery than the iPhone 5, so maybe thats why you think the iPhone 5 is charging faster.