Originally Posted by
SpammersAreScum
How early I do it has no effect on the length of the Diamond extension as far as I can tell -- they give you an extra calendar year. As noted, I plan to have an IC stay in mid Oct, and I intend to use the free weekend night as part of it. And I didn't want to wait too late to book for fear of rates going up.
You can book the AMB weekend rate without actually having the voucher in your account. What matters is that you have it in there when you check in..