As seem some difference in opinion re if promotion works, and number possible under promotion, just thought I would report that I (an existing customer) had no difficulty in registering 5 at the promotional rate. I did them all on one order, not sure if that matters.
For those who tried WHC in past, and were put off by their archaic system for setting TXT and other DNS records (you had to create a separate free hosting light service which billed you $0 per month to change them), I am happy to report that they, a couple of months ago, added new integrated features so it is easy to do domain forwarding, set DNS records right within domain management.
It is easy to turn off auto renew within domain management as well.
Bob