You make this sound much harder than it is. It is not difficult at all.
Ha! Based on my experiences of the past I would say it can be very difficult. I think I mentioned originally I am fairly computer literate.
Also, when I called at first and had the person explain how you use the cert on-line she said to me something to the effect of, "if the number of certs you have does not match the number of nights the system can have problems."
Also, when I called before my trip because I was worried that it said "points" on the reservation they told me, "I see that... the certs are out of your account but they are NOT attached to the reservation." She assured me she fixed it.
Lastly, it didn't work out so no matter how hard or easy it is it did NOT work and I lost both the points and the certs and had to call to fix it. I guess my only point to people is to watch closely when you use the certs so you don't lose both. Not a big deal.