Have the rules changed again in the last few months?

From what I read a few months ago on the UK immigration site you either needed £18,600 in earnings OR £16,000 in savings. I was just reading about a guy that was £700 short of £18,600 earnings and he had to make that up with £17k of savings!

Why would it work that you need more savings if your only £700 short on your earnings?